Overheating issue

**Elite6** · 03-31-2012

Did LIM full job a few months back including new tep sensor in LIM
New Water pump
Rad looks brand new
New rad cap
Tried 2 thermostats now
Coolant flushed

About a week ago car was overheating fairly quickly once it go up to temp, no idea why so I pulled the t-stat right out and voila no overheating in fact car barely registered on needle during long drives & idling. I figured a bad t-stat.... got another 195 degree stocker again today and boom car overheating!

Upper rad hose feels hot but not tons of pressure. If I crack the bleeder at idle RPM coolant will stream out then stop (this is when the car is already at 212 deg). To help facilitate the air bleed I rev up the engine to 2K and hold. I expect coolant to come flying out as it passes the t-stat but I get absolutely nothing. However, when t-stat gone coolant flows out like a champ.

Need help here folks!

**Fivefingerdeathpunch** · 03-31-2012

Im kinda stumped aswell.

But the thermo aint in upside down is it?

**tu8i1o7** · 03-31-2012

It sounds like you still have air in there somewhere. Try taking out the stat, filling the manifold with coolant, and put it back together. Remember it still needs to be bled until its a steady stream. Also make sure that the radiator is topped off before and after you do this.

**Elite6** · 03-31-2012

Thermostat in properly, coolant elbows replaced too.. Perhaps it is such a huge air pocket that it is preventing the flow of coolant past the thermostat? still stumps me how removing the t stat made it all better. I will fill manifold at thermostat housing and try.

**thomas mcnulty** · 03-31-2012

clogged radiator, had it happen to me before. just because it looks new doesn't mean anything.

**GTP in RTP** · 03-31-2012

bad coolant temp sensor ?

**Elite6** · 03-31-2012

Coolant sensor i suspect is ok because it was low during the time i had no t stat. Plus didnt seem far off when electric fans went on. I filled the LIM directly to top and no difference. I am no engine guru but cant make sense of why when i hold revs at 2000 and crack the bleeder i get zero flow?

If clogged rad... How to proceed? I did get a coolant flush and figured rad would have been unclogged then.

**matt5112** · 03-31-2012

no flow.

So there is no coolant flowing there or the level is too low to hit the bleeder.

**Elite6** · 03-31-2012

Originally Posted by matt5112

no flow.

So there is no coolant flowing there or the level is too low to hit the bleeder.

How can i explain that things seem perfectly fine when i get rid of t stat?

**matt5112** · 03-31-2012

the t-stat is defective?

Did you buy a guaranteed-to-fail? (aka fail-safe)

**Elite6** · 03-31-2012

If it is defective it will be the second one in a row that has performed the same. The first t stat actually opened up in boiling water. They are not fail safes..

**matt5112** · 03-31-2012

Honestly I never use the bleeder.

Just fill it up a bunch, then drive the piss outta it while watching temp.

typically doesnt move much, then i top up the rad once its cool and i'm good to go.

**Elite6** · 03-31-2012

Once it gets anywhere close to operating temp, the temp starts going up fast. Went around block and was up to about 220. But while no t stat no problem.

**matt5112** · 03-31-2012

Tried buying a 180?

**Elite6** · 03-31-2012

No i figured a stocker should work just fine

**matt5112** · 03-31-2012

2 out of the thousands they produce per year actually makes the odds that you bought two defective ones seem much higher than you'd normally think.

Whos T-stat did you buy?

**Elite6** · 03-31-2012

Moto**** from psource

**matt5112** · 03-31-2012

motorad.

Which ironically is the company that manufactures the high flow t-stats that ZZP sells.

And CT/PS is the only company in canada that carries them.

Try a prestone or stant (see any other part store).

Or a 180.

**NASCAR Pace** · 03-31-2012

Does the service engine soon light come on?

**Elite6** · 03-31-2012

No lights come on assuming they work. Will try Napa I guess. What kind of an effect does drilling a small hole have if this remains an unsolved mystery?