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Not your usual cooling problem...

swift6

Yoda
Offline
Three inches of snow overnight at the casa. Sun has already cleared what was left on the streets though. Tonight is supposed to hit 9 degrees. Off to visit relatives in Kansas and Nebraska for the holiday so I'll try to keep up with my own thread over the next few days but it may be difficult.

On to the cooling issue... with my TR8.

While a V8 in an LBC (even when its designed to have one from the get go) might unsurprisingly have overheating issues my TR8 does not. Even on 100+ degree days the temp gauge only eeks past the halfway mark as the fans kick into high speed mode. The only time that the temp gauge ever stayed above the halfway point was in stop and go traffic on a 100+ degree day with the A/C running. Even then, the high speed mode of the fans was able to keep any overheating in check.

When the mercury dips to the other extreme is when I have cooling issues. As in the engine has trouble actually reaching operating temperature! If I let it sit and idle (for 20 minutes or so, no exaggeration) the engine will eventually get warm enough to open the thermostat and circulate all of the fluid. If I don't, the coolant doesn't seem to get hot enough to even open the thermostat. If it does, then the just about any airflow is enough to drop the temp gauge down to the 1/4 mark or more.

Example, this morning after finally getting the car up to temp and I'm off to work. Temp needle hanging out between 1/4 and 1/2. Less than 1 mile later, at barely 30 mph, the temp needle is dropping below the 1/4 mark. Turn onto a main drag and pick up speed and the temp needle continues to drop towards C. Pull into a gas station for one of my soon to be patented gas station mocha's, stood in line for a while, the whole time the TR8 is outside idling... (Please no Global warming chastisements...) temp gauge got back up to near 1/2. As soon as air is moving through the radiator again the temp needle keeps on dropping. The higher the speed, faster the airflow, the more it drops.

It occurred to me that it could be a wonky temp sender but that wouldn't account for the drop in heater output as well. So I think that the temp sender and gauge are fine. The only thing I can think of to do is to restrict the airflow through the radiator a bit and see if that helps.

Any other ideas floating around out there?
 
If the radiator is warm at all when the temp gauge is showing below 1/4, most likely the thermostat is bad or sticking. I'd replace it "just because", with a Robertshaw brand if you can find one.
 
Did that last night. Tested it before installing it even. Brand new one from NAPA and it worked fine in the pot with the candy thermometer.
 
I once had a TR4 that spent most of it's life in California. I ran a 160 degree thermostat all year round. About half way through an Upstate New York winter, when complaining about the heater not working, a friend asked "Are you running a summer or winter thermostat?" I had no idea what he as talking about, but when I put in a 180 degree thermostat, voilĂ , heat.

Might be your problem.
 
There's always the old "cardboard in front of the radiator" trick.
Have you ever noticed the over the road trucks with the bib or shutters on the grille?
Same principle.
Jeff
 
Update from the road... from a coffee shop in Hays Kansas.

Pulled out a questionable 185 degree stat (haven't tested it yet, I'm in Kansas) and replaced it with a 195 (tested) stat.

Considering the cardboard trick since it doesn't overheat at idle. Though I would continue to watch the temp needle like a hawk. OTR trucks and their diesel engines are horrible for producing heat in the winter which is why they use those covers. Might devise a quick fit and removal cover for those days that we get over 50 throughout the winter. Which happens a lot.

Just curious if anyone else had any other ideas.
 
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