Author Topic: overheating GTV  (Read 2051 times)

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festy

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Re: overheating GTV
« Reply #45 on: January 14, 2022, 05:10:46 PM »
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.
 
 

poohbah

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Re: overheating GTV
« Reply #46 on: January 14, 2022, 08:33:03 PM »
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.
Now:    2002 156 GTA
            1981 GTV
Before: 1999 156 V6 Q-auto
            2001 156 V6 (sadly cremated)

festy

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Re: overheating GTV
« Reply #47 on: January 15, 2022, 07:54:35 AM »
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.

 

poohbah

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Re: overheating GTV
« Reply #48 on: January 15, 2022, 10:16:55 AM »
Doh... stupid me. For some reason  I thought it may have had a vacuum line running from it. No idea why.
Now:    2002 156 GTA
            1981 GTV
Before: 1999 156 V6 Q-auto
            2001 156 V6 (sadly cremated)

Colin Edwards

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Re: overheating GTV
« Reply #49 on: January 15, 2022, 12:23:34 PM »
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?
Present
2020 Giulietta Veloce
2018 Abarth 124 Spider
1987 75 3.0

Past
2015 Giulietta QV
2009 159 3.2 Ti Q4
2012 Giulietta TCT Veloce
2006 147 Ti 2 door Selespeed
1979 Alfasud Ti 1.5

poohbah

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Re: overheating GTV
« Reply #50 on: January 15, 2022, 12:56:27 PM »
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.
Now:    2002 156 GTA
            1981 GTV
Before: 1999 156 V6 Q-auto
            2001 156 V6 (sadly cremated)

Craig_m67

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Re: overheating GTV
« Reply #51 on: January 15, 2022, 05:46:47 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?
'66 Duetto (lacework of doom)
'73 1600 GT Junior (ensconced)
'03 156 1.9JTD Sportwagon (daily driver)

poohbah

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Re: overheating GTV
« Reply #52 on: January 15, 2022, 07:51:45 PM »
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.
Now:    2002 156 GTA
            1981 GTV
Before: 1999 156 V6 Q-auto
            2001 156 V6 (sadly cremated)