Coolant Temp Reading

[Dr. JL]

Just got my new-to-me 1991 red/ivory NSX up and running after replacing the ALB accumulator and front struts. I absolutely love this NSX! Well, the temperature here in north-central Texas finally cooled down below 50 degrees F and during my 20-mile trip to work this morning, I never saw the water temp gauge move off the peg. On the drive home, the CEL illuminated with the OAT around 60 degrees F with the temp gauge still on the peg. The temp gauge registered up to two bars at a red light, then returned back to the peg at highway speeds. The CEL light does not illuminate after it sits off for a while when started back up. Am I missing anything other than a failed-open thermostat?

 

[goldNSX]

You can check both coolant hoses under the 'bonnet' during warm up. One should be considerable cooler than the other one after 2 minutes normal driving. If they're both medium warm the thermostat is stuck open.

 

[Dr. JL]

Changed out the thermostat today. The rubber seal that stops coolant flow until 78 degrees C was completely gone! I suppose it had never been replaced in the NSX's 225,000 mile life. Temp goes to 4 bars and stays there now. Easy $32 fix!

 

[Dr. JL]

Coolant leak

So I've changed the faulty thermostat and added coolant. I'm thinking happy trails, right? Nope. Last night I found a basketball-sized pool of Honda coolant on the shop floor. During install, I torqued the thermo housing bolts iaw the service manual. The hoses in and out of the housing are relatively new and look good. Thinking I didn't seat the thermo absolutely perfectly, I removed and reinstalled again today but, still have the leak after warm up. Out of ideas. What do y'all think?

 

[comtec]

Check the plastic coolant tank for cracks.

Mike

 

[Dr. JL]

No tank leak. Coolant is leaking from the thermo housing coupler seam. I don't think the original thermo was ever changed out since the NSX's birth so no housing damage caused by NSX techs/DitYers along the way. It all buttons up nicely and you can feel "resistance" against the bolts as it tightens down against the seal.

 

[lazyboyz69]

Changed out the thermostat today. The rubber seal that stops coolant flow until 78 degrees C was completely gone! I suppose it had never been replaced in the NSX's 225,000 mile life. Temp goes to 4 bars and stays there now. Easy $32 fix!

Did you ever find the rubber seal? Maybe its stuck inside still thats why its leaking.

 

[Dr. JL]

The coolant that leaked out during both my replacement and reseating of the thermo had very small bits of rubber. Too small and too few to cause a leak during seal (all clear before closing it all back up). Still racking my brain over this one....

 

[Dr. JL]

I've decided to slap a little Hondabond HT around the thermo seal and button it back up. Should do the trick. Thanks for the inputs.