Thanks for the info. I know the ECU has the capability of commanding each fan individually and that's what we did in the tune but perhaps I will have to look at the wiring and either rewire it to do what I want or just have them both come on at the same time. I'm getting the car back next week for a few days and will look at it then.

 

The fans are more efficient if you let them run in tandem like they were designed. All the PCM can do is ground the relays. As they are wired, they will not run individually. Why do you want them to run individually?

 

I thought with starting the primary a little earlier I would be able to control temps better during times when the ambient temp was not as hot. Maybe I will leave them in tandem but first I need to address the radiator issue.

 

There is no primary and secondary. The two fans run together and have a Hi and Lo speed.

 

Not meaning to but does it look like this? http://cgi.ebay.com/ebaymotors/HYPER...5fAccessoriesI tried looking that part no up and it seems to be for gen 1 motors and not gen 2. I may be wrong but just double checking. I do know using a standard gen 1 t-stat will cause problems!!

 

That link doesn't work.

 

try it now.

 

When I ordered it from the dealer it was supposed to be for an LTx engine and the GM one I put in looks just like what I took out of the car, but that being said, I always thought the reverse flow thermostats looked like the one in your link with a secondary spring at the bottom but this one does not; however, it looks like the one pictured on Summit's website as a Hypertech 1008 which is listed for that application but does not appear to have a secondary spring. So now I'm confused as to what this should look like.

 

I can tell you that the hypertech and the stock t-stat looks like the picture above. I am going on summits page now.

 

An LTX looks like this.

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Here is a link from zip corvettes http://www.zip-corvette.com/Zip/prod...FBF915BCE3FBE1

While the part no. is correct at summit, the picture is wrong.

 

Interesting, that's what I thought they looked like but that is definetely not what I removed from the car and it doesn't look like what I put back in although, it was supposed to be for an LTx. I appreciate that, and maybe whoever worked on it before me put the wrong thermostat in the engine and the owner didn't know that it was running warmer then it should. I'm going to look into this more and pickup another thermostat from Napa and take a look.

 

I drive around Fresno on summer days (I have clients near the Airport), and in traffic, 217-225 - then fan kicks in and back to 217. And, on those relatively fast Fresno freeways, about 205.

The ride is a 94 LTI have a brand new radiator (stock), water pump, and coolant... and the interior space that collects garbage is clean. I think that's as good as it gets for me... it seems to be working as designed.

- WPK

 

Thanks that's a good point of reference. My shop is right by the airport.

 

Evan,
1. The reported temps sound about right for an LT-1 C-4

2. radiator trash is usually the problem.

3. My 95 gave me fits. It would idle for two hours in 95F temps with fans cycling exactly by the FSM numbers. I would drive it, stop in traffic and sharp temp rise and puking.

The system would hold pressure ... no liquid leaks. However, I noticed when using a vacuum fill, it did NOT hold a vacuum. Appears either a small head gasket exhaust leak into the cooling system OR as GM calls it 'casting porosity'.

I used one of the fine particle additives and solved the problem. After about 2 years and 15,000 miles, it runs perfectly.

With the reverse flow LT 1 the leaking exhaust gas is trapped and causes a gas void which causes hot spots and puking. Probably most engines have micro exhaust gas leakage into the cooling system, but passes easily out via the pressure cap. LT 1 with reverse flow and high engine rear geometry traps gas voids.

Tell you driver to monitor both the digital and the analog temperature gauges. If the analog leads (increases at a much faster rate) than the digital temp rise, it is gas void in the engine cooling passages (the analog is located in the rear of the engine, digital in front at pump). They should move together.

Joe

Several other LT 1 drivers spent big bucks with Chevy service centers and never solved the problem but were successful with this approach.

 

Thanks Joe, I will take a look at that. He has told me the analog reading is always greater than the digital reading when he has compared the two.

 

Is this true? On my 96, the digital is always lower than the analog. With the analog its hard to tell exact what the temperature is because the gauge is not linear.

 

Mine are pretty close.

THE POINT is not minor difference in reading, BUT if the analog increases in temperature at faster rate.

Such as stopped in traffic... analog goes from 200 to 220 in a few seconds and the digital moves from 200 to only 210 after 2-5 minutes.

Joe

 

Mine does not change that fast, but the analog is always higher than the digital. If I remember correctly, the last time I checked it, the analog gauge was almost at the shaded mark, and the digital indicated ~225 when the fan came on.

 

I put a dewitts radiator in my 95 LT1-It still runs around 200 hwy driving and it will rise up to 228 in traffic if the a/c is not on.I thought by using this rad the temps for cruising would be about 190 with a stock stat but I was wrong-It will take a little longer for the temps to rise compared to the stock radiator. I kept everything stock except for the rad. Running that hot will make the trans temp run hot that is why Im putting in a trans cooler
I would go back to the stock thermostat and start from there.