Hi All,

My 87 Iroc 305 tpi has been having quite a bit of work done on the injection, mostly my fuel regulator. I've developed a situation where it's running a little warm. When I stop if I hit the radiator cap a few times it will release water into the overflow quickly.

Do you think my cap is bad, causing the quick release of water and making the car run warm?

Thanks for the help

 

It shouldn't release water when you tap on it. Replace the cap.

You can't really do work to the fuel pressure regulator. It's there or it isn't. You can replace it... that's about it.

How warm is warm? Do you hear the coolant boiling? 180? 280? Replacing the thermostat isn't very involved and with all the work being done to the fuel pressure regulator, I'd be sure to put in a new thermostat.

Replacing parts is a hobby that comes with ownership of an F-body...haha

Goodluck!

 

No kidding, hobby!
Yes the regulator was actually replaced. The car in normal driving now is running about 220-230. When I go up a hill it does go up to around 230 and a little higher. Like I said if I shut the car off at that point and tap the cap the overflow will quickly rise. Not alot, but it does concern me.

 

replace the cap, but i would try to see if there is any temp drop from the inlet and outlet of the radiator, where im getting at is see if your rad. is clogged. Also check your airdam to see if its still on there nice and tight.

 

I'll check the air dam. Why do you think it would burp up when tapping the top of the cap?

 

Ok, I got the new cap on and that seemed to fix the problem of coolant burping into the overflow when I tap on the cap.

I have another question for you guys. My temp gauge seems to work fine until the car gets to around 220. At this point it seems to bounce from 220 up to 230 then back to around 200. Do you think the gauge is bad?

 

gauges on GM vehicles of that era are notoriously bad. I have an aftermarket oil and temp gauge mounted above my radio for that reason.

 

Buy a lazer temp gun, a multi meter with a temp probe, SOMETHING TO CHECK TEMPS WITH...

This will tell you if the guage is correct. The sensor that tells the guage what to say may be bad too somehow.. Should be in the side of the cylinder head.. driver side? Is it possible the wire is laying on the exhaust manifold?

Fans are working fine??

Can you see thru the radiator fins ok? at least when you put a flashlight behind it?

 

What temp does it hold on the highway, steady cruising?

In stop-and-go the stock fans don't kick on until some fairly high temps. Many rig a manual fan switch for the 2nd cooling fan for this reason and/or go with a lower temp fan switch and chip with a lower primary fan cut-in temp. Lowering fan cut-in temps won't help a lick if it's running hot on the highway, though.

 

I am having the same issue OK I have a 1986 IROC-Z TPI 305 that is overheating. I Replaced the motor Put in a NEW/Rebuilt AC in it Replaced the water pump and New Radiator. It seems to run at about 200 degrees with the AC off and over 230 with the AC on. I even sent back the Crate motor and replaced it but is still overheating. Shroud is there and Fan is on connected Direct. I am just stumped now. any info can help...
I evern replaced the CAT....still

 

It probably has a 195* thermostat. If I remember right that's stock temp. and a lot of motors are gonna run hotter with the AC. Try putting in a 180* thermostat and see if that helps. You'll also want to adjust the temp that the fans come on at. Or else put a manual switch on it that you can work yourself.

 

Hey guys,
Thanks to everyone for the suggestions. I put a new cap on and the problem was solved.