Help diagnose a truck anyone?

[J-Mech]

Originally Posted by Shrewcub

I agree with Jonathan, but will add in the hundreds of water pumps I've done on these engines, I've never had an air lock. I don't use an Airlift to fill them either, I just pour it in and top it off once its running. They are about the only thing I don't use it on.

I've done a lot of water pumps on these also. I have had a few that air locked while filling. The system is set up to self bleed, but the ones I had that didn't, had a bad or plugged air bleed hose. So.... not really a systems fault, but it can happen.

To be sure, I start filling the system with a hose off. Once the water pump is full, I go from there.


The only odd thing on this is the fact the gauge was showing overheat, but no heat out of the heater.

[jimbob200521]

Originally Posted by J-Mech

Was the t-stat bad, or did draining and refilling the system get the air out of it?? Sorry man, gauge pegging, but no heat out of the heater..... I still don't think it was a bad t-stat. I think changing it fixed it because it was air locked. You even said yourself that you don't know if you got the air bled before just changing it.
Edit: the more I think about it the more I think it was the thermostat all along. In a previous post I had said that adding coolant and burping the system the best I could did not resolve the issue. The only time the overheating went away is after I replaced the thermostat.
Edit: the more I think about it, the more I want to say it was the thermostat all along. Like I had said before, the coolant never seem to drop since I've had the truck until the sudden overheating issue. Even adding coolant and burping the system the best I could did not solve the problem. It was only after I replaced the thermostat that the issue was resolved.

One way or another it got fixed. I just hate it when you don't know the root cause. Especially on a forum, where others can read later.

It was probably both. In an earlier post of mine, i stated that after adding a bit of fluid I restored heat but didn't fix the overheating problem. This why I replaced the thermostat.

Edit: the more I think about it, the more I believe it was the thermostat all along. Even at adding coolant to the system, and doing my best to burp any potential issues away, I was never able to get the overheating issue fixed. It was only after replacing the thermostat that the issue was resolved. I'm not saying coolant wasn't an issue but I think it was a misleading symptom. Either way I needed to add coolant which restored the heat but the overheating problem still persisted.