Overheating And No Heater At -40

[misterp]

Hmmm well usually when I've ran into a bad water pump it would be making noise or frozen-up. I would say the thermostat is refusing to open, either there is an air pocket on the engine-side of the tstat, or the radiator-side is so cold as to keep it from opening. Either way you might try drilling a 1/8" hole in the plunger so that hot water & air is allowed to circulate even when the thermostat is closed.

 

Mr. P.

 

I think you might be on to something, it seems like when the engine is hot (block heater) and the ambient temperature is very cold is when this happens. You think it might be the differential in temperature between the engine and radiator

 

OK this sheds a lot of light on the subject - I once had the same thing happen to me 15-years ago in CA, it was 10-degrees outside and I did not put enough antifreeze in the system, anyways driving to work and my truck overheated; I pulled over to the side of the road and found the upper hose boiling hot but the bottom hose frozen completely solid with ice, the entire length of the hose. And I suspect this is also happening to you. The top hose can be frozen because the hot coolant will eventually thaw it out (heat rises) but the bottom hose if frozen solid will never thaw without warm ambient temps.

 

On drilling the thermostat plate, I have not done this myself but what I have been told is that the little hole will allow hot water to penetrate to the other side of the thermostat and if there is ice or icy water on the other side it will warm it up enough to allow the bi-metallic spring to actually get warm and open. Theory is that the cold water on the "outside" of the thermostat is still keeping the bi-metallic spring cold and hence not opening, and a 1/8" hole (or two) in the plate will not affect engine warm-up to a significant degree. FWIW.

 

Mr. P.

[Fast2500Ak]

i've seen coolant un mixed with a freeze point at -60, the optimum here in vegas is -34. sounds to me like your water pump isn't pumping. get your truck to operating temp then feel the surge tank. engine overheating and heater core not getting any flow of coolant, sounds like a lack of flow to me. if it were a t stat you would still have cab heating.

 

 

 

 

Good point, bit it seems like it isn't working for a while. Heres a few examples.

 

 

The first time was a few weeks ago, the first time it got good and cold. I autostarted it twice and came out to find no heat and the temp needle a few ticks past normal. I let it cool down a bit and fired it up and it went completely back to normal.

 

A few weeks later I take the truck out and after a while of no heater I noticed that was up to temp and started to worry, I turned around and got it to my gramma's house. This time it was a bit warmer closer to the top of the temp gauge but I got it shut off before it got into the red. I let it sit a few minutes and again it was fine.

 

I went out to the dorm parking lot. -40 and I drove it over to my gramma's house, and again it overheated, not badly (Thank god Fairbanks is such a small town). I twisted the cap and let it puke up a half gallon of coolant then refilled with strait dexcool (no water). After about 10 min it was fine.

 

This morning it did it again only it about halfway it started working again. It was right as it pushed past norm temp it snapped back and the heater fired up.

 

 

When it comes back online its sudden, the heater blows hot and the temp drops back to normal.

 

If I have ice in the lines it could be when the ice melts it starts working again, is that a possibility? It just seems to resume too suddenly to be a pump. But I might just replace it anyways, cheap insurance even if it doesn't work.

 

Thanks again for all the help!

Edited February 9, 2008 by Fast2500Ak (see edit history)

[detjoe]

here is a shot in the cold... is your belt spinning the water pump? as cold as it is I would check eveything, your belt could be slipping???

[Fast2500Ak]

I think you might be on to something, it seems like when the engine is hot (block heater) and the ambient temperature is very cold is when this happens. You think it might be the differential in temperature between the engine and radiator

OK this sheds a lot of light on the subject - I once had the same thing happen to me 15-years ago in CA, it was 10-degrees outside and I did not put enough antifreeze in the system, anyways driving to work and my truck overheated; I pulled over to the side of the road and found the upper hose boiling hot but the bottom hose frozen completely solid with ice, the entire length of the hose. And I suspect this is also happening to you. The top hose can be frozen because the hot coolant will eventually thaw it out (heat rises) but the bottom hose if frozen solid will never thaw without warm ambient temps.

 

On drilling the thermostat plate, I have not done this myself but what I have been told is that the little hole will allow hot water to penetrate to the other side of the thermostat and if there is ice or icy water on the other side it will warm it up enough to allow the bi-metallic spring to actually get warm and open. Theory is that the cold water on the "outside" of the thermostat is still keeping the bi-metallic spring cold and hence not opening, and a 1/8" hole (or two) in the plate will not affect engine warm-up to a significant degree. FWIW.

 

Mr. P.

 

I'll check to see if its frozen, thanks again I think this is probably the cause.

 

 

here is a shot in the cold... is your belt spinning the water pump? as cold as it is I would check eveything, your belt could be slipping???

 

 

 

Yes its spinning

[SS_bnoon_SS]

Theory is that the cold water on the "outside" of the thermostat is still keeping the bi-metallic spring cold and hence not opening, and a 1/8" hole (or two) in the plate will not affect engine warm-up to a significant degree. FWIW.

 

Mr. P.

 

Just FYI, you only want one hole in extreme cold climates. I used two in my '86 Trans Am and it flowed to much through the two 1/8 inch holes that it never got over 140-150 degrees (on a 180 stat), which is WAAAAAAAY to cold to try to defrost a windshield at 0 F or below.

 

As a side note, drilling a small hole can also help purge trapped air out of the coolant system. Some stats even come with small holes in them for these very reasons mentioned in this thread.