My '81 GTV has developed a tendency to run pretty hot, including bubbling in the expansion tank like an espresso machine on shut down while dumping coolant out the overflow pipe.
It did it the other day (it was a very hot day admittedly) and reckon I lost about 300ml after turning the engine off.
I have checked the coolant and can find no evidence of oil in it, and have also checked the oil and can find no coolant in it either . No signs of milky brown sludge - I even took a sample of oil from the sump and cooked it in a spoon - no bubbling, crackling or hissing to indicate water/coolant in it, so I don't think the head gasket has blown.
I have also tried to bleed the cooling system in case there were any air pockets. Hasn't done the bubble and dump again, but it does seem to get over 80C pretty quickly and then push up to 90C or more in traffic after much shorter time than normal. But other than that, the car seems to be running fine, and no obvious extra strain.
Any tips? Could it be the rad has some kind of partial blockage perhaps?
Head gasket failure can also (sometimes) allow combustion gases into the coolant .. causing over pressure etc. There is a product in the UK that can be used to sniff the coolant for hydrocarbons, bound to be something at your local rad / mechanic that can do similar (sniff the coolant for burnt/unburnt hydrocarbons).
Just a thought (this happened with my JTD)
Cheers Craig, yes my obvious concern is head gasket but as noted I can't detect any coolant in the oil, or vice versa. No smoke, steam of any type, and no hissing either. I suppose I should get a compression gauge to test compression, to make sure. I haven't done one since high school, so it might be an interesting experiment! I guess there could be microscopic split so not big enough yet allow fluid past. Really hoping it's just a fixable cooling system problem, not a head gasket since I've just spent a pile buying the GTA and fixing stuff I needed to pass a pit inspection.
How's the tuning on the car? All stock? Timing? One thing to check is the fan is wired corrrectly so air pushes towards the motor and not sway from the motor reversing the leads which is easy to do can cause this issue also another tip if you don't have air con connected you can wire both fans in series to run together for some extra cooling benefit goodluck
Cheers mate, car has standard timing. Next checkpoint for me is the thermostat to see 8f it's stuck in closed position. Couldn't get it off when I tried last week. Interesting about AC. I have disconnected AC and removed the compressor a couple of years ago. The fan for AC is attached in front of the rad and I don't actually think it is working at all.
First thing to check is thermostat is opening fully.
A simple test for head gasket is to squeeze the hoses while the engine is running. If there is extra pressure the hoses become hard although if it is a very small leak you may not notice.
Possibilities that are easier to fix (than a head gasket!):
Engine tuning
Blocked thermostat
Blockage in radiator
Flush the block and reverse flush the radiator
Check fan operation
Piggyback second fan - if you are not using AC anymore, wire the two from a single relay with the two 87 pins feeding the two fans. If nothing else you will get a better fan outcome because it will now be getting 12V instead of maybe 9V after it goes through all the spaghetti from the fusebox!
Cheers for that, will try the various suggestions on the weekend. I like the wiring the two fans suggestion, though I may come back with some "how to" questions.
If the AC fan in front of the radiator is redundant - then remove it. Its just adding unnecessary mass to the car and getting in the way of air reaching the radiator. If you need to run two fans to resolve the overheating you are just smothering the real issue. The root cause of overheating must be found before more damage is done!
thanks Colin - prior to the suggested rewiring, I had actually been thinking about removing the front mounted AC fan. But it is a PITA to get to.
But regardless, I'm focused on working out the why its started running hot. And thermostat seems most likely culprit.
Ok, front mounted fan I would just dispense with. I was thinking you had a dual (side by side) fan setup. As Colin said, you need to fix the root cause. That said, Perth summer...you probably need all the cooling you can get! My dad has just installed a larger, more modern fan in his Alfetta sedan (also in Perth) to help ensure it doesn't overheat with the AC on.
Now I know this sounds weird
But but a 50grams of fine ground black pepper and put this in the tank ie radiator and run the car at idle til around 85 deg so the thermostat opens
And turn off leave until it cools down
Then drive as per normal
It does work
Ripkeys believe it or not
Cheers guys.
Carlo that does sound bizarre, so bizarre that it sounds a bit witch-doctory.
But maybe worth a shot. By ground, do you mean a really fine grind? And would you put it in the overflow/expansion tank? My rad doesn't have a cap of its own.
Yes fine ground black not white pepper in the expansion tank
thanks mate. I might try it after I've had another go at the thermostat. Ideally would like to fix it properly.
I hope this is not stating the obvious, but why wouldn't you just pull the radiator and get it flushed. If its never been done just think about how much gunk is in there after 40 years. I did that on my GTV about 10 years ago . I also took the opportunity to add another core to the radiator. Never had an over heating problem since including 10 seasons of club sprints
That would be totally sensible Paul. At moment just trying to limit expenses, having just bought the GTA and spent a couple of grand to get it roadworthy.
I can't remember how accessible a 116 radiator is, but when the engine is warm place your hand on the core to check it's relatively consistently warm across the surface. If there is a cool section, it's likely the rad is partially blocked.
And the pepper idea is to fix a pinhole leak (rad/casting/headgasket). I don't know how it would remedy overheating from other faults?
cheers Beatle, yep you're right about the pepper. There are no indications of a leak in either the rad or any hoses (or it wouldn't have come out of the overflow).
I appreciate everyone's input. When I get a chance over weekend (hopefully) I'll check the upper/lower hoses as it initially warms up to normal temp as suggested, and then try to get the thermostat housing off. It does seem like that is a likely culprit.
If that's not it, I'll move onto the radiator.
I've got three weeks off over Xmas coming up, so I should have time to have a proper fiddle about. In between selling the 156 and hooning around in the GTA...
Quote from: poohbah on December 09, 2021, 09:55:50 PM
I've got three weeks off over Xmas coming up, so I should have time to have a proper fiddle about. In between selling the 156 and hooning around in the GTA...
Don't forget the fire extinguisher . . . . . ;)
all good bazz - three Alfas. three extinguishers.
Given the age of the vehicle, the radiator has brass tanks and is entirely serviceable. You should do this irrespective of what ever other faults the cooling system may have. This gets you to a base level to start any other diagnosis. Without being certain of the cooling abilities of your radiator, chasing other faults will never give you certainty.
From there a list of faulty contributors:-
1 Faulty/inoperative thermo switch.
2 Faulty thermo fan
3 Poor power supply to thermo fan (Voltage drop, low current supply)
4 Faulty thermostat
5 Overflow pressure cap has poor location, has old hard rubber, not holding pressure. System running at atmospheric pressure.Replace cap with original. If using aftermarket, it needs a 14 PSI cap with the correct reach and seal radius. Do not overlook this.
Cheers MD,
Good points. Just to confirm, the fan comes on a the correct temp and runs full speed, so fan switch appears to be fine. I also replaced the cap on the overflow tank with a recommended one a little while ago as the old one did appear to lack sufficient tension in the spring. It hasn't boiled over since, but is still running hotter than normal.
Time to rip out the radiator and take it to the most experienced specialist radiator mob you can find.
Hand the radiator to one of their "experts". If this mob is any good they will be able to tell within seconds if the radiator is suspect - just by the feel of it in their hands.
All things being equal, a partially clogged radiator will be heavier than an unclogged radiator. A very experienced radiator "expert" will know straight away what your radiator should feel like. If it can be re-cored they will recommend it - and probably suggest an increase in capacity / surface area while the header tanks are off.
You know the saying "All roads lead to Rome?" Well, substitute the word radiator for the word Rome.
If you elect to re-core the radiator, nominate no more than 12 fins per inch. Major red light overheat warnings on the 75 series is due to too many fins per inch (over20) and the fans cannot pull enough air through during idle time at traffic lights in hot climates like Qld. Usually not a problem on the move but in stopped or slow moving traffic, yes worrying the shit out of 75 owners.
Also you could be running a lean mixture unknowingly. Have you checked the condition of the carburetor coupling rubbers for fractures top and bottom?
I haven't read the entire post but will just add that water pumps do get disintegration of the impellers so all that is moving is the shaft with very little circulation.
Ya just need a need a chocky moove poohbah
(Or inspiration via YouTube from the original TV commercial)
https://youtu.be/gVMqa26xRDs
Great yarn sportiva. About ten years ago, I remember making multiple treks from the side of the road to a water trap at a local golf course to fill up a dumped 600ml coke bottle when the top hose on my first 156 split near the clamp. I sawed off the split end and reclamped it so I could get home.
I do plan to get the thermostat off once I'm on leave next week. I'll provide an update when I have news to report.
So I don't have to find a choc milk carton - what sort of gasket will I need? Does it usually come with the replacement thermo or do I need to buy it separately? And should I also use some kind of sealant as well? I reckon there is sealant of some type on the current thermo housing, which is probably why I couldn't get it off last time.
ok thanks
Sportiva's yarn reminded me of a dodge fix we did on a Nullabor crossing in an early 80's Saab. The upper radiator hose developed a split and was leaking. Not much chance getting a suitable hose on the Nullabor so we cut a piece of cardboard from a Colgate toothpaste packet and used a hose clamp to hold it on. A year later we still hadn't changed it...
It's been a while since I messed with a nord thermostat but from memory it is fairly easy to pull out, seal and drive away so I would go that way first before pulling radiator out.
do we have the answer it wasnt the cap was it?
but i change that regularly ,i have seen them rust off
Haven't got to it yet, Carlo. Doubt it was the cap as I changed it. It hasn't boiled over again, but I haven't really driven it far enough to know, though it still seemed to run hotter than normal. I have bought a new thermostat, gaskets and sealant so i Intend to get the old one off this week.
Heading for 44 deg C today in Perth...... :o
+42C the last three days in a row at my place. I have walked out to start on it twice and turned around and came straight back in to the AC again.
And all of a sudden the GTA, in black on black, is not sucha cool place to be...
I've hit a bit of an obstacle.
Managed to remove the thermostat, which required some persuasion as it was sealed tight with sealant.
Popped it into a pot and brought it to a boil and basically nothing happened that I could see. So it would seem that it is buggered.
Unfortunately, the replacement thermostat I bought from Repco (a Dayco item that I was told was suitable) will not fit as the one in the car appears to be OEM, and therefore a combined housing/thermostat unit (pictured).
The only other apparently suitable alternative that Repco, Autobarn and Supercheap could identify is a Tridon model that is pretty much the same as the Dayco, and is meant to slot into the existing housing. They are an entirely different size, shape and 'style' to the OEM one which has a central locating pin extending from the top that sits in a collar in the housing.
I was able to remove the OEM thermostat from the housing by pushing down on the spring and rotating the centre clip, but that's not much use if I can't find a replacement.
So for the moment I'm stuffed - will try my Alfa workshop in the week to see if I can source an OEM or NOS part.
Unless anyone else has any suggestions?
Cheers Sportiva,
I was going to ask whether I could just drive it without one til I find a replacement. Might also provide extra proof of whether it was the thermostat that was the issue.
I'd prefer OEM if I can find one, don't fancy hacking out the retainer posts.
I recall reading somewhere that someone instead swapped it for a 105 housing, and that fits normal Tridon or Dayco thermostats?
That would present pretty much the same problem though - I'd have to find a 105 housing first.
Searching online, looks like I can get a genuine replacement for about $120. But I'll try the alfa workshop first.
yep, already removed the thermostat from the housing. Which is very easy by simply pushing down and twisting the retaining clip - and totally at odds with Haines which advises to never try and separate the two as '"the components cannot be separated..."
Soooo.. whack the housing back on and take her(?) for a decent fang!
(Italian tune-up, mileage and results may vary, never mix on a double demerit point weekend)
So, I have now managed to buy an OEM thermostat (ie the full assembly in it its housing) - no local parts stores had them and the local Alfa workshop (Cileberti Motors) I go to was closed last week for the NY break.
Went back to the workshop on my lunchbreak and walked out with the requisite part in 10 mins. Part cost $108, but that is about $50 cheaper than getting the same part online (including the postage).
All going to plan, I'll get time to fit it on the weekend.
Update.
So I finally managed install the new thermostat. What should have been quite a simple job ended up a right PITA.
First, when removing the old housing, the inboard retaining bolt came out with the socket - which I didn't realise til hearing a double ping of it bouncing off something. Spent at least half an hour trying to find it without any luck (no idea, not on the ground, nowhere in the engine bay i could see). Bloody witchcraft. It simply dematerialised.
Regardless, it would have been worthless anyway. As it turns out, the thread in the bottom half of the housing must have been either partly stripped or worn down, because neither the matching bolt from the other side nor a new matching size bolt would screw tight - about 2/3 of the way in it would just start rotating.
So had to find a longer bolt the same size and just fitted a nut to the other end. Not ideal, but does the job.
All done methinks, I'll give her a whirl.
Crank crank crank - nothing. And after a few attempts, of course I've also now drained the battery. Swearing by this stage - I then glance at the fuel gauge. Nothing, absolutely empty. Dry as the Great Sandy Desert.
When I parked her up a month ago, I know there was still some fuel in it - but after a week of +40C over Christmas, I figure what was left in the tank and fuel lines must have evaporated.
Doh - what an idiot to overlook something so obvious.
So I go and get 10L in a jerry can, pour it in and check - yep fuel gauge is now showing a quarter of a tank. So I drag out my jump starter and try again.
Same as before, crank crank crank - click click click - no start and now my jump starter needs recharging again too.
Bugger - decide to call RAC. The plug in their battery jump starter - still nothing.
So they go through the usual checks - spark yes, fuel - hmmm - still no fuel getting to the carbies. Use hand pump to suck fuel up the fuel line and try again.
After a few tries - bingo. She's Alive!!
But coolant is streaming out from the thermostat housing. I jump in to tighten up the bolts - they're tight, but still there is coolant coming out. WTF...
Then it dawns on me - back when I first removed the thermostat a month ago, I also loosened the air bleed screw. But I had only popped it back in without tightening it.
Couple of turns with the socket wrench and all tight as a drum again, no coolant leaking and engine running fine.
Take her for a spin - uh-oh, now the fan isn't coming on as it should when getting above 90C. Bugger. But i clean the thermo switch wires on the rad and clean up the power wire connection to the fan (think it got damp from coolant etc) and fan comes back on when its meant to.
Feeling smug - so I go for another spin.
And of course - thing is still bloody running hotter than it should. Even though the old thermostat was definitely buggered, the new one doesn't seem to have made a difference (surely it can't be a dud too...?). Generally now sitting closer around 85-90C in normal running, and heads toward 100C if I'm sitting stationary for more than a minute or so (even with coming on). At least its not pumping coolant out the overflow like it did a few weeks back.
So I'm back to square one. Now thinking maybe its time to yank the rad, give it a flush, and or get it refurbished/replaced
But I've got another problem - where the hell are the bolts located that hold it in place? Damned if I can see them.
Any one able to advise? My Haynes manual just says remove the mounting screws but it only shows the single big mounting bolt on the top. Where (and how many) are the others? I sure can't see any.
(Sorry the pic is not great).
As I understand it (long, long time ago), there's just that one bolt at the top. The bottom of the rad has two lugs that fit in holes in the rad cross member. Same as an Alfa Sud/Sprint
Cheers Craig - that explains the pic in Haynes then.
Yes, the radiator is held in by just that one bolt at the top.
If the radiator is significantly blocked, you can often tell just by getting everything warmed up (thermostat properly open) then shut off the engine and feel around the back of the radiator - it should all be vaguely the same temperature.
If you find cool spots (often at the bottom) its a sign of blocked tubes.
Running without a thermostat isn't a great idea and can give misleading results anyway, because with the thermostat removed the radiator bypass hose is always fully open. In normal operation it gets progressively blocked by the plunger on the bottom as the thermostat opens.
Many years ago I had an Alfetta cooling problem that ended up being fixed(?) by restricting the bypass hose flow by sticking a piece of garden hose inside it IIRC.
I can't remember the specifics, but something was causing the thermostat plunger to not sufficiently close off the bypass.
Cheers Festy,
As a matter of interest, would the fact that air bleed screw at the top of the thermostat housing was "open" contributed to fuel not being drawn up the fuel line to the carbies?
I imagine it must - which would explain why even the RAC guys had trouble getting enough fuel into the carbies.
Quote from: poohbah on January 14, 2022, 08:33:03 PM
As a matter of interest, would the fact that air bleed screw at the top of the thermostat housing was "open" contributed to fuel not being drawn up the fuel line to the carbies?
I imagine it must - which would explain why even the RAC guys had trouble getting enough fuel into the carbies.
No, there's no possible way those two are related.
Your fuel pump probably just needed priming, and if the fuel line is empty it can take quite a while to draw fuel all the way from the tank.
In this situation if you pop the vent covers off the tops of the carbs and tip a little bit of petrol into the bowls, the engine should then run long enough for the pump to prime itself.
Doh... stupid me. For some reason I thought it may have had a vacuum line running from it. No idea why.
Taking longer than usual to prime the fuel system could suggest a partially blocked filter somewhere. If the fuel flow is restricted and lowers the carby float bowl level, the engine may be running a bit lean. This may contribute to the overheating?
The fuel filter seems clear, and I've had no trouble with starting since.
I also don't want to jinx things as I haven't been able to do a decent run in traffic, but apart from the immediate short test drive after changing the thermo (when it still ran hotter than I'd like) it does now seem to be holding around 80C - at least beyond the point at which it was previously heading north to 90C.
I won't be convinced til I've taken it out for a proper test - hopefully will get time today. At this point I'm going to assume any optimism is misplaced and that the investigation will have to continue.
Quote from: poohbah on January 15, 2022, 12:56:27 PM
The fuel filter seems clear, and I've had no trouble with starting since.
How old is the hose (it collapses on itself, before leaking...)
Is there another filter at the tank, or inline
What about the little basket filter things in the carbs just before the needle valve...
But yeah, I don't think the fuel system is in anyway related to your overheating problem.. just another "while your in there, scope creep" hole to go down.
Has anybody pressure tested the cooling system?
No, haven't pressure tested the system. Just got back from a longer drive, and while it is definitely better than before, after being stuck behind a slow coach 4WD for a fair while, it did end up hovering around 85-90C mark for the rest of the drive home. So still needs further investigation.
I'm sure this is just peripheral to the issue, but yesterday I discovered the clamp on the main bottom hose from the rad where it joins the water pump and 3-4 of the little retaining nuts on the top edge of the pump assembly were not tight-tight and there was some dried residue from old coolant seepage around them. So they are now all tightened up.
Also - what's the giveaway that a hose should be replaced - squishy or firm? The bottom hose is definitely pretty squishy.
More often than not the lower hose "should" be firmer than the top hose. The lower hose is usually not subject to as much engine rock, vibration or movement as the upper hose. The upper hose should be more flexible than the lower hose so as to not stress the radiator inlet and engine outlet fittings.
If your going to replace one or two (recommended) hoses, would be a good time to have the radiator professionally cleaned. Looks like it needs a bit of love!
Thanks, when I get around to pulling out the rad I'll probably replace at least the main ones.
Any updates on this?
Did you get to the bottom of it?
Interesting read.
I have a track car with an overheating issue, keen to know what yours turned out to be.
Haven't gotten round to pulling the rad or changing hoses yet, as I have hardly had the car out for the last few months. Just got her up and going again after winter slumber and no overheating issues in the 40 or so minutes I had it out on the road. But I will get around to it now weather is improving - need to source the hoses first.
Last two days had a more immediate issue - getting it started. I had to suck fuel up to the carbs and the old plugs were completely cactus. But have fitted new ones and all good for now. Except will need the carbs balanced and tuned. Big carbon buildup on plugs from cyclinders 1 and 3, and the other two were black and sooty, so seems it is running rich in general as well as having uneven mix between individual cylinders.
Wow - September since I last mentioned any progress.
Good news is I finally got around to removing the radiator today and am pretty certain I now know why it was running hot after about 30 mins.
While the core looked fine on the inner facing side, it was crumbling in two separate areas on the front facing side where it was hidden by the AC condenser. To be honest, I'm amazed it managed to function at all.
Dropped it into a local radiator shop and they are making me a new one with bigger more efficient core made of newer materials, and I should have it in about a week's time.
Also took the opportunity to remove the condenser (also in poor condition) - I had previously removed the compressor and rest of the AC anyway - which should significantly improve airflow to the new rad. I'm probably going to replace the two main rad hoses while access is easy - they're in okay nick but I may as well.
And I've been able to scale off the surface rust on the body/support under the radiator - it was a little bit crusty under where the core was crumbling.
So hopefully, I'll have a properly functioning cooling system in the next week or so.
But wondering whether I should look at fitting dual fans - the old rad only had the one, which might be sufficient when I fit the new one.
Fabrication of the new radiator took a bit longer than initially expected, but I picked it up on Friday and fitted it yesterday.
System fully flushed, filled with fresh coolant, fan refitted and running as normal. I took the hoses into the workshop a couple of weeks ago to ask about matching replacements, but the guys looked at 'em and reckoned they were basically as new, so no need.
Took it for a decent run today and worked beautifully, sat around 80 the whole time, and fan kicks in as it should if it gets over it. With the old AC condenser removed, the rad now has much better airflow.
Now I just need to get onto removing the inlet manifold and carbies to replace the mounts and flange gaskets - definitely got a vacuum leak on the front carby.
But the nuts are super tight - I'm a bit wary of snapping studs, so will need to think my way through. For now, I'm just happy I can take her out without fear of cooking the engine.