alright guys i've got a 1992 camaro rs 305 tbi engine basically stock except aircleaner and chrome. My car has now overheated on me in countless occassions, i've replaced the waterpump, and thermostat and the radiator is an aftermarket 2 or 3 row modine radiator which looks to be very new (no dings dents or anything yet). I'm basically running all water in the system right now and the only thing i could figure is my radiator cap wasn't pressurizing properly but, after buying a new 1 and installing it i'm still quite doubtful that is my problem.

The only problem i can really find with the coolant system so far is it has the typical steady intake manifold coolant leak on the front edge of the block. I'm lazy and i realy would rather not have to pull it and regasket it plus it's my daily so i'd much rather i didn't have to. I guess if i have any more problems i'll try pouring a thing of radiator stop leak in it and hope that it seals (most doubtful the leak is fairly steady).

O btw yes my fan is kicking on at the proper temp 220-225*. The t-stat is also opening at 195* as it should.

My only 2 thoughts are maybe i have a slightly blow headgasket at the front of my engine on the driversid along with the intake manifold leak or #2 the leak is substantial enough that is bleeding off all the pressure the system is under causing it to boil.

I did pressure test it and yes it does bleed off pressure but, it takes it about half an hour to do so, so i guessed most likely it would bleed that much off through the pressure tester fitting (could be wrong here).

Anyways any advice is helpful thanks.

 

Have you checked your timing? What condition is your airdamn in?

 

Make sure your air dam is in place, not torn apart. You will see a 50-75 degree difference with a factory style air dam.

 

air dam is good and in place but, timing is 10* advance i have played with the base a lot and i know that's a lot of base timing especially for this engine but, it performs best with the 10* base. It has 145k miles on it so the chain has 4* of stretch approximately therefore it's basically like running 6* btdc timing.

ps i got rid of my coolant diverter valve and routed it to the heater core all the time and bought a new radiator cap and haven't had a problem since.

 

10* is waaaaaaaaay too far advanced for a stock TBI engine. You shouldn't be running more than 6*.

How do you know it's running well? Your knock sensor is probably having a good time, i'm not even sure 91 would combust properly at that great of an advance. Have you datalogged it? Getting any knock counts?

Please do yourself a favor and retard your timing a bit... that might be your problem right there.

 

Ya, that is quite a bit...6 might even be pushing it, but I wouldn't go any higher than 6.

 

If his intake is leaking coolant, could it also be leaking inside, and filling the oil with coolant, watering it down? I know when you remove the intake, the coolant flows into the lifter valley, and into the oilpan.

 

Alright the distributor says 10* advance but, it's only truly getting 6* advanced because, after 145k miles the timing chain has stretched about 4*.

No it's getting no knock counts on 87 octane and yes it does run best at 10* i've played with it a whole whole lot.
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No that's not happening for sure but, thanks for the idea and keepem coming.

I replaced the radiator cap and got rid of my coolant diverter valve and have coolant running to the heater core all the time now. Haven't had a problem since this but, the problem was only simulataneous before so we will see.

 

have you had any problems since, my car is doing the exact same thing and im pretty dumfounded on what the hell is going on