need your knowledge..re cooling

[JRKOUPE]

hey y'all.....

help me out here...

while my s50/e30 is on track she is good at halfway mark.....but occasionally I see the temp needle "dancing" a bit....I have all new good grounds.

Coming into pits hot the temp needle will start to climb as my mph drops....and there are times the add on elec fan will not even come on...even as she is close to red zone....I don't run a clutch fan.

2x last week after a run group she spit coolant out of overflow while she was shut down but still hot....

on the grid the temps would climb to 3/4 or so, but once moving on track she'd go back to halfway....

I noticed on my mishi rad that the left tank and the upper hose was crazy hot and the hose was kinda hard, but the rt tank and lower hose was just warm at most.

There are times my elec fan seems to come on at the proper time( and at these times both hoses seem hot!).....but not consistently. Ive been driving her to and fro work this week...30 miles each way on hwy.....

The fan switch has been checked and is good.

And again, at speed she is steady w/ the needle at halfway.

Am I experiencing a bad water pump or a wacky thermostat?....Im thinking one or both.

.its almost like thermo is stuck closed at times....

ill do both as its the smart thing for me to do for this track whore....but Id like to know how to intelligently go about diagnosing this..

can a thermo on the way out work well intermittently?...

like a fool I did not r and r when the s50 was initially put in....


thanks!

[Jaxx_]

are the grounds on the cluster good? The temp gauge has 3 prongs on it... from what I remember, one is sensor signal. one has 68ohm resistor to ground, and the other is 12V. If the ground gets bad the temp will read high. If you tap on it, often it will return to it's usual mark.

I would assume that the thermo switch is turning on at a consistent temperature, but the gauge is reading erratically. I would swap thermostats because you had your coolant overflow, just in case it is sticking. I think it is, but usually it will stick as it is warming up, not as it is up to temperature. They're a few bucks. Just replace it, I'd say.

You need another way of measuring the temperature, rather than relying on what you think is hot, and what the gauge is saying. Just past the 1st 1/4 mark is right around 165F in my experience. 190 is right about midway. 220(i think it was) is around 3/4. YMMV.

what coolant are you running?

[JRKOUPE]

I run bmw anitfreeze/water

My gut is that it is NOT the cluster....

when both rad hoses and both tanks are hot she works fine and fan goes on properly.....

for some reason there are times only the lt tank and lt hose is hot......and even then once she is up and running she runs cool.

[Robotin]

dont know much about track cars.. but if your hoses are hard in one area.. and soft in another.. u have a clog somwhere..

i have always taken my thrmostat out and let the water run freely...

[atmobenzin]

sound like waterpump to me