Overheating but not really? Air in system or other problem? Need help diagnosing (Page 5/14)
olejoedad NOV 09, 02:07 PM
Good thoughts Patrick...
Cold cabin and hot engine at idle, hot cabin and cool engine at RPM....

It is flow related, I'm thinking water pump, even though it is new.

I suppose the flow issue could be a blockage, but it would have to be before the T-stat housing - internal to the engine - to see those results IMHO.

Cebix, what does the car do if you remove the thermostat and drive it?
Patrick NOV 09, 02:15 PM

quote
Originally posted by olejoedad:

It is flow related, I'm thinking water pump, even though it is new.



I was wondering that as well... and if it was a 2.8 I'd suspect a slipping plastic impeller, but this is a duke.

If the OP was local, I'd go have a look just out of curiosity... but Poland is a long drive.
cebix NOV 09, 04:04 PM
So they supposedly flushed the cooling system when rebuilding the engine. They said some crap came out but not much. But I think I'll get it double checked by another shop.

Did I mention I had the same problem before the rebuild? I even linked my old thread some posts ago. That was with the old water pump which also wasn't that old, only a few years. I think it's an Airtex if I remember correctly and it had the metal impeller, same as the new one.

EDIT: I guess a blockage inside the block is unlikely since it is a rebuilt engine. I haven't driven that much without the thermostat but it seems to work awesome without it if you ignore the long get up to temp time from a cold start.

EDIT2: I do think a blockage in the heater core is probable. And it is the "short circuit" as we call it here since it's before the thermostat. However I guess I would never have much cabin heat if that was the issue? Is still an air pocket a probability from all these posts or are you guys certain it's flow?

[This message has been edited by cebix (edited 11-09-2019).]

olejoedad NOV 09, 08:58 PM
If it runs ok without tstat, drive it that way for a day or two. Meanwhile, check the tstat in a pot of hot water and see how it acts, when it starts opening and when its full open.

Keep checking coolant level.

[This message has been edited by olejoedad (edited 11-09-2019).]

cebix NOV 10, 12:49 AM
My both previous tstats (Stant) didn't pass that test and they were both new. They didn't open at all in a pot of boiling water. Could they also need some pressure? One I drilled through to have a small flow of water. The symptoms were the same. Now I have a Gates one and didn't check it that way yet. But I do have flow through the rad, it's hot plenty so I guess it's working alright?

[This message has been edited by cebix (edited 11-10-2019).]

olejoedad NOV 10, 11:52 AM
Pull the stat, drive it a bit and tell us how the car responds to the change....
cebix NOV 11, 01:34 PM
All right, drove it for an hour around the city with no thermostat. Here are my observations. It's 42F here outside.

1. It took forever to get up to temp but that's understandable. Good 15-20 minutes until the temperature gauge reached the second mark. Was turning heat on and off at this time to check heat but not to rob the engine of its temperature in this state. Heat was good even very early on. When up to temp it was blowing very hot like it should I guess. After this it runs great, no sudden temp rises or drops like with the tstat in.
2. However after idling for a minute or two it will slowly creep up to almost 220. Didn't stay around for it to stay higher but it would come down slowly to the second mark when driving around. Really slowly I guess, slower than it should? I stopped for gas, it took a few minutes while the engine was shut down. When I turned on the engine, the rad fan was blowing (it wasn't when I shut the car off) and the temp was a little above 220. Gave it some gas getting off the pump stand and it fell very quickly to the second mark just like with the t-stat it. Then again with driving no fluctuations but at idle it was rising slowly again to 220.

All hoses are hot and stiff. Couldn't check the coolant yet as the engine is still hot. Rad hot to the touch, rad cap plenty hot. Overflow tank didn't overflow, no noticable hisses, leaks. The hissing I was describing before I'm not sure of now - it might be something else since I can hear it coming from the engine too... but I guess it still might be an air pocket.

Do you guys have any thoughts about this?

EDIT: Checked the thermostat in boiling water... it does NOT seem to open. It stayed for a while in the water, I pulled it out and in again... nothing. What the hell, do I have 3 new broken thermostats or does it need pressure or whatever else to open?

[This message has been edited by cebix (edited 11-11-2019).]

Gall757 NOV 11, 02:02 PM

quote
Originally posted by cebix:

EDIT: Checked the thermostat in boiling water... it does NOT seem to open. It stayed for a while in the water, I pulled it out and in again... nothing. What the hell, do I have 3 new broken thermostats or does it need pressure or whatever else to open?




It is a 195* thermostat.....boiling water is 212*.... so the thermostat should be open. no pressure required.
cebix NOV 11, 02:10 PM
Would I get a hot radiator and hoses, etc. if it wasn't opening in the car? If it wasn't opening ever wouldn't have I overheated a long time ago on the highway?

[This message has been edited by cebix (edited 11-11-2019).]

olejoedad NOV 11, 02:19 PM
If its not opening in a pan of boiling water, its not opening in the car at 195°F.

I think you have gotten some bad thermostats.
Were they all bought from the same source?

At this point, I would ignore the hissing sound and concentrate on getting a good thermostat in the car.

Solve one problem at a time.....