Welcome to the Corvette Forums at the Corvette Action Center!

Running hot or not ??



I just had a total rebuild and now the engine may be running hot, the car always ran faily well heat wise, pretty much flat at 205. I had the block machined 20 over and now that is all back togher Im showing 240-250 or so on guage.

My mechanic did two heat sensors all new hoses and a radiator flush, which he said looked fine (the radiator). I also have a brand new edelbrock water pump and 160 thermostat.

After a while he finally ran it with the radiator cap off and took a reader from the coolant itself with a manual meter. It was right at 200, while my guage was reading at 250.

What would cause the gause to suddenly go out of wack after a rebuild, and how can I correct it. Or could it actually be 200 in the radiator and 240 inside the block ??? Any better way to test this ?? I really want to be sure its not going to burn up after all the money I spent on this rebuild.

Any info would be apreachiated.
Jan 1, 2002
Washington, Michigan
'67 Marina Blue Convertible
99% of all the replacement temp senders are improperly calibrated for the Corvette gauge; the only one I've found that's even CLOSE is the Wells #TU-5, available at AutoZone for $6.00.

Why did he replace the original senders - were they not working? They're the only ones that are accurate.


my mechanic replaced the sending unit becuse the temp guage seemed off to him.

I am now under the impression something is drastically wrong with all the guage. I had it out for the first time at night and all of the guages go wackey with the lights on. I turn on the head lights and the temp guage goes way up over the red, I get about 3 amps higher on the volt meter and a 1/4 tank more gas on the fuel guage.

If I turm my light on and off a few times I can get the temp guage back down to 205 or so, where im guessing the temp actually is. Now I have no faith in any of the guages. The only guage that stays the same is the oil temp.

I wouldnt think all the guages would all go at once like this. Any idea what could be cuasing this and or where to begin trying to fix it ??



Sounds like you've got a ground problem.

Have you checked to see if your wipers and heater are working, if not you'll be looking for a ground wire at the starter hooked to the wrong post.

Don't feel alone, my guess is most of us shark owners either do or have had a ground problem at one time or another.

My car won't start right now without a jump, and then when I hit the brakes my amp gauge goes to the negitive, I've also had to insulate my interior light. It turns on as I go down the road.

Btw, I hate working on car wiring!!

Goodluck to you,



Heater and wiper still work. And the guage seems to back to normal today, unless of course I use my lights. I will check the starter, is ther any other gound under the dash I should also check ?


Oh yeah , there are plenty of ground wires in the plastic fantastic.

If your gauge seems to be working again it's probably just a loose wire ground or otherwise.

I'll be digging into mine soon too!



I had similar temp problems after my engine was rebuilt. A recently rebuilt engine will run a little hot as all the new parts and bearings break in. Also, leaving a temp sender in the engine during the hot tank cleaning will ruin the sender and make the gauge read hotter than it really is, but I suppose that couldn't be your problem since your mechanic replaced it. My vette would get up to 220 or 230 right after the rebuild. We ended up ordering a sender from either Mid America or Ecklers (can't remember which) that was advertised as being specifically calibrated for the vette. We also installed a high-flow 160 degree thermostat you can get from Auto Zone. It's been in the mid 90s a lot lately and I've limited myself to short trips, but so far it hasn't gotten above 215.

My guess concurs with the above -> wiring problem. Something probably got jostled loose when the engine was pulled or when it was re-installed. You'll probably find yourself disassembling the console to get at the gauges. When you do, try cleaning the internals of any gauges that look dirty. My oil pressure gauge read very low when I first got the car, but it turns out that all it needed was a cleaning.

Hope I've been of some help. Good luck.


I think you've got a ground wire problem. Check the Assembly manual, but I think that the gauges are grounded through the engine ground strap, and considering the recent re-build, perhaps you have a bad , loose, or dirty connection.

Steve :w

Corvette Forums

Not a member of the Corvette Action Center?  Join now!  It's free!

Help support the Corvette Action Center!

Supporting Vendors


MacMulkin Chevrolet - The Second Largest Corvette Dealer in the Country!



Advertise with the Corvette Action Center!

Double Your Chances!


Top Bottom