Too much cooling

[holywood3645]

I live in So California and previously had some (over)heating issues with original OEM S4 radiator, when in traffic. I purchased a Griffin alloy 12 x 22 x 3 that fitted in to the original location. I knew I was going to rebuild the car including motor, but the rebuild motor spec changed and I opted for a less powerful 1700 cc QED420 spec super sprint motor (140hp ish).
My problem: I think the engine is not running hot enough. Only if I sit in stop and go traffic the temp gets near 190 Deg F. On a really hot day in normal traffic it runs about 155 to 160 Deg in normal trafific. In the evening driving it running about 130 Deg to 140 DegF. It appears the alloy radiator is providing too much cooling
I have the original S4 OEM rad, that I can replace it or possibly block off some the cooling area on the alloy item installed,

Advice and input always appreciated
James

[types26/36]

James,
Have you tried running a "hotter" thermostat?

[ericbushby]

I agree with Brian.
The thermostat may be faulty as it is intended to shut off the water to the radiator gradually as the temperature falls . I don`t think you should not have to modify the radiator at all.
Eric in Burnley
1967 S3SE DHC. ( can`t go out in it, as it has rained here nearly every day for a month)

[gjz30075]

Are you certain the temps you're reading are correct? Get readings with a thermo temp gun to verify what you're seeing on the guage. What thermostat do you have in the car now?

Greg Z

[collins_dan]

I would love to have this problem! I would agree with checking the accuracy of the gauge. I once thought I had this problem, but it turned out the gauge was dying. Two questions. Do you have an oil cooler? What did you use for exhaust manifold and was it thermocoated in anyway (jet coat or tape)? Thanks, Dan

[holywood3645]

I?m travelling at the moment and will not be able to pull the thermostat until next week. I?m not sure which one I have installed. The header question, Yes, the exhaust manifold is ceramic coated. I used the titanium coating offered at Electo-tech (link below)
I do not have an oil cooler installed, and will verify temperatures with an IR gun when I return. I checked the temperature gauge prior to installation by inserting it in boiling water before installing and it read correctly at that single point (212F), it read 210F. It was slowish responding, but nothing that gave concern.

http://electrotechcoatings.com/ceramice ... anium.html

Thanks for the replies
James

[holywood3645]

Ok, I pulled the thermostat that turned out to be a 71Deg item and replaced it with the Waxstat 78 deg 'stat from the original motor. The result is improved it drives and sits around 160 Deg F with no huge jumps or dips. One thing i noticed is the thermostat I took out did not have a bleed by hole (the one i replaced it with did) I also looked for a bleed opening in the seat and don?t see it there either.
Ambient temperature was 75DegF when tested; also it is a 13 PSI rad cap.

The rise and drop in temperature is now smooth, with no jumps or dips. Could this be attributed to the lack of bleed in the one that I replaced?

What operating temperature should i be aiming for? We have a VW Golf that runs at 190Deg F

Thanks for the input.

James

[m750rider]

My 1969 S4 seems to run best about 85 C and I think I have an 87 C thermostat in there. In summer in traffic it might get to 95, in winter it will hold about 80.

Bob
1969 S4 SE
45/8842

[69S4]

My 1969 S4 seems to run best about 85 C and I think I have an 87 C thermostat in there. In summer in traffic it might get to 95, in winter it will hold about 80.

Bob
1969 S4 SE
45/8842

Much the same with my 69SE (Strombergs). Perhaps even a few degrees cooler round the 80C mark would be better if I could get it down that far in warm weather. By the time its got to 95C it's definitely out of its comfort zone.

[CBUEB1771]

also it is a 13 PSI rad cap.

I have always stayed with the standard cap which is closer to 7 psi. I made this decision when I had a 1970 MGB GT many years ago and blew a couple of core (freeze) plugs out of the block when I changed from a 7 psi cap to 13 psi cap.