How does one check for proper circulation / water pump problem?

[JesusOnIceSkate]

Is there a way to check if waterpump is working / coolant is circulating? I think the coolant in my 95 GT is not circulating....this is part of exhaustive diagnotic of the overheating problem in this thread:

http://forums.stangnet.com/showthread.php?t=727624

 

[Dino Dino Bambino]

I am afraid that there are bigger problems here however. Last week I took the car out on the freeways....it ran hot on streets at about 20-30 mph average as I was expecting, but on the freeway it cooled down to MA of NORMAL.

Last night I decided to take it for a drive (I love this car since my daily driver is a sluggish SUV) on freeways expecting it to run cool....no luck it's overheating on freeways now as well ! This is with new radiator and thermostat. When I came back the temp needle was in red...and the fan was blowing...but apparently not helping much. I checked upper hose to see if there was any appreciable pressure...it was hot but pressure-wise not much different from when engine is cold..does this mean anything? I know this is a loaded post and I appreciate you guys reading this. I guess my questions are:

1. Does high-temp (Temp gauge reading past L of normal) resistance of 2660 (normal is 700-1000) indicate that sensor is bad?

2. Am I looking at a bad waterpump? I'm assuming that at freeway speeds, fan or no-fan the circulation should be adequate to cool the car. Since there is no pressure at upper rad-hose (as there was b4 I changed radiator) I'm assuming water is not circulating due to bad pump.

3. I plan to remove remove thermostat and disconnect the ECT and take the car on freeways again this weekend (this insures that fan is blowing and new 180* balanced mr.gasket thermostat is not restricting flow). If the car is overheating am I correct to assume the waterpump is a gonner?

4. When the needle on temp gauge is on MA of normal...what temp is this approximately? And when it's border-line red what is the temp then?

Thank you again for all your help

1. A resistance of 2660ohm should put your coolant temp. at about 198*F, which could mean that your gauge is very pessimistic 'cause at that temp., the gauge needle should be between O and R.

2. One way to find out if the water pump is bad is to remove the thermostat. If the upper radiator hose remains soft without a thermostat, you definitely have a coolant circulation problem (bad pump). If it goes hard, your problem was a bad thermostat.

3. If you disconnect the ECT, the high speed fan should stay on all the time but that won't help you if the engine overheats on the highway.

4. MA on my gauge is 212*F (100*C) but yours could be different. The far end of the NORMAL band beyond L is about 240*F.

If your gauge readings go higher when you operate the electric windows or switch on the lights, I suggest you add an extra ground cable between the upper intake manifold and the firewall. It's very simple and cheap to do. The engine grounds on our Mustangs are poor and you might be surprised at how much difference a proper ground can make. You may even find out that this was the problem all along.

 

[Zero_chance]

You should be able to feel if the stat opens in the upper hose. Best bet would be to get a laser temp reader. Does car have heat? Last resort could be to pull a heater core hose and start car. Aliittle messy but a sure way to check flow.

 

[HISSIN50]

If you have an IR or contact thermometer, you can check things out throughout parts of the system. As an e.g., I recently was doing this to test heat rejection through the coil.

Good luck.

EDIT: oh chit, when I loaded the page, there were no replies. Sorry for redundancy.

 

[Zero_chance]

At least were both on the same page. I surf on my playstation 3 so by the time I write a reply the problems usually resolved.

 

[go-stang5.0]

no one mentioned this...or at least I didn't see it...but could the system need to be burped?

 

[Dino Dino Bambino]

If the t'stat opens properly, the system should be able to burp itself. You might need 3-4 heat cycles to completely get rid of the air in the system.