I replaced the rad and hoses this past summer (it was totally rotted out) and all of my overheating issues went away until winter arrived. In fact, the needle on the temperature gauge barely climbed off of the bottom in nice weather. Temperature control in the passenger compartment was not an issue.

 

Now that winter is here, I have no heat in the passenger compartment most of the time. When the engine RPMs are low (<2500, i.e. when I'm cruising along or stick in traffic), the needle on the temperature gauge rises, sometimes into the red zone, and I get no heat. When the engine RPMs are high (3000+) heat will come out of the vents and the needle drops to the bottom. It's feast or famine with the heat, except that it's more famine than feast and the feast is pretty meager.

 

I didn't replace the thermostat and I'm thinking it could be the culprit. Perhaps it's sticking or maybe the previous owner installed one that was rated for a lower operating temperature, or something completely unrelated. Any ideas or suggestions?

 

Thanks,

Brian

sounds t-stat oriented

 

OEM is recco'd, 193 deg in winter.

 

Make sure the spring is toward the block.

 

Burp any air out of the system may also help

Check your cooling level (including reservoir). A low level can give you the "hot-cold" symptoms.

 

Also, check your heater core inlet/outlet hoses after warm up to see if the coolant is hot and flowing into and out of the core. If the coolant is cold or lukewarm, it is indeed the T-stat.

good luck, John

the fact that the heat is rpm related leads me to suspect the water pump, the fins can be corroded and thus not pumping enough coolant around for the engine to stay cool in traffic

the fact that the heat is rpm related leads me to suspect the water pump, the fins can be corroded and thus not pumping enough coolant around for the engine to stay cool in traffic

 

That was my first thought as well :-\

 

There is a way to check them without pulling the water pump completely off.

 

Remove the upper radiator hose, as well as the metal pipe to the water pump. Then you can feel inside to see what condition the fins are in.

 

Would probably need to buy another pump to compare them to. If they're the same, can probably return the new pump.

 

-Dave

the fact that the heat is rpm related leads me to suspect the water pump, the fins can be corroded and thus not pumping enough coolant around for the engine to stay cool in traffic

 

+1

I just had the same kind of issue in my Loyale too. I replaced the Tstat, but the problem persisted. I had bought the cheap $3 tstat though, the next time I went up, I bought the "superstat". After installing that one, and bleeding the system for maybe 10 to 15 minutes (it's winter, hard to get to temp), I had no more issues. Also, the heater core is an easy place for air bubbles to hide, jack the front of the car up while bleeding the system, it really helps. I would start with the cheaper items like that first. Just an idea.

I'll start with the the t-stat. I just bought a decent one (the same one that the dealer uses - they buy aftermarket now, apparently). If it is the water pump (a secret dread, lurking in the back of my mind), is it a difficult replacement?

 

BB

If it is the water pump (a secret dread, lurking in the back of my mind), is it a difficult replacement?

 

BB

 

I think it's you're pump. It's not a tough replacement, but you probably want to get a timing belt set and install it at the same time. There are decent PCI kits on EBAY for about 65 with shipping for belts and tensioners.

 

You'll want to read the timing belt right up.

Hi, folks. I thought that I should close the loop on this topic. I bought a water pump and t-stat and so far I've managed the time to replace the t-stat. Heating and cooling is much better, so I think that my issues were just the t-stat. Once I get a couple of hours on an upcoming weekend, I'll throw the new water pump and new timing belts in for good measure.

 

Thanks for you help, everyone. Rusty the Wonder Car is running great.

 

BB