I have a 1987 L98 in my ride and i am having a heating problem..
Facts:
Stock Radiator..
305 water pump..
Board .30 over
10:1 comp
cam'd
Head's
and that is it

Problem...over heats bad!!!!!!! what should i do?? burp or what??? band new motor and dont want to blow it! :confused:

 

Have you pulled the radiator out. If not start there and look threw it. Mine was clogged up with all kinds of stuff right where the fans pull from.

 

I'm experienceing a similar problem on my '89. And I've been trying to solve it for about 2 months now! The car still overheats bad, and I don't know what it is.

I'd suggest starting with the simplest stuff, then move your way to the more difficult (and expensive) work.

Here's the sequence of events that I've used - as I did each thing I would run the car to see if it would overheat. When it did, I moved on to the next item:

1. Changed the rad cap.
2. Removed the rad and had it pressure tested and flushed. Cleaned debris from rad tray at this same time too.
3. Checked spark plugs for discoloration - suspected burning coolant.
4. Replaced upper and lower rad hose (make sure you have a spring in both hoses! - learned this one the hard way). And I'll warn you now, the lower hose is a NIGHTMARE!
5. Replaced thermostat with a 160degree 'fail safe' unit (the ones that fail in the open position).
6. Checked ignition timing for advance -- too much advance can cause an overheating condition.

This is as far as I've gotten and, like I said, my car still overheats. It won't overheat at idle, but once I start moving, the temps go right through the roof! So my next steps are going to be:

1. Replace water pump
2. Cooling system pressure test - suspect a blown head gasket :(

I sincerely hope your problem isn't something serious - like a blown head gasket (or worse, a cracked head). But the only option you have right now is to systematiclly eliminate each of the above items until you find the problem.

Good luck with the car.

 

When I pulled the radiator and flushed the system two weeks ago, I cut the operating temp down to between 195 and 210.......

Start with the simple stuff first, and then move to the more expensive.....

I would venture to guess that pulling the radiator and cleaning it (along with straightening the fins) will cure about 90% of the overheating problems with these engines.....

 

I'm running a stock replacement radiator I bought from O'Reilly's Auto parts last year when my original radiator sprung a leak in the plastic tank. My engine runs really cool with a 180 stat; even in Texas heat. In fact I had to put in a 195 over the winter months to get heat into the car.

Here's what I did:

Stock water pump and pulleys.

I followed TPIS' recommendations and blocked the bypass hole in the passenger side of the block (lowest hole where water pump bolts up); I drilled four holes in my thermostat. I use the basket (Robert Shaw type) thermostat; not the flat "silver dollar" style.

I packed the coolant using the "rev it with the cap off and fill the radiator while the R's are up) method.

My PROM turns on the fan at 190 F. At highway speeds - 70 MPH /2000 RPMS -, my temps stay in the 180s. When I come off the interstate, my temps climb into the 190s, then drop back to the 180s.

This is in 90+ degree ambient temps too. Of course, when the ambient temps climb into the 100s, this picture will change by about 20 degrees F.

With all the fooling around I've done with coolant and oil temps, I've concluded that it's airflow that's the culprit. Get the airflow through the radiator up and temps plummet.

Also, it's been my experience that it's retarded timing, not advanced timing, that contributes to higher coolant temps.

Hope this helps.

Jake