My 87 is overheating.

I had a head gasket problem and that was taken care of.

this is the third time the heads have been done, so I have no idea of how much has been taken off of them.

System gets flushed at least every year, about a year ago we had the
Plug and knock sensor out.

We only had to take .008 off this last time, it lost the fire ring on 7.
Imagine that.

It is a .60 over motor built to stock specs by Jasper using my original core with a Procharger D1 and intercooler.

It has been running hot since we did the heads last week.

I have the biggest "Griffin" radiator that they sell for a stock 87.

edlebrock water pump, Mr gasket 180 thermastat.

We did a CO2 test on it today and it came back negitive.

new sensor and sender

when the gauge reads 250 the ecm is seeing (input) 238.
That is getting above my comfort level.

I am not sure how hot it will get, but it never ran that hot before.
Even with the bad head gasket it ran about 225 max, it just lost coolant.

The only thing I can see that changed is the thickness of the heads and the design of the intake gaskets.

Everything looks clean at the radiator, intercooler and condensor.
fan seems to be working ok.
I have not taken them out, but we had it on the rack today and it looked clean, the only place you cant see very well is between the condensor and the rad.

ignition is set at 6 BTDC.

System has been burped.

Got any ideas? I am at a loss at this point.

thanks Greg.

 

I also am running about 70% distilled water to 30% green coolant plus water wetter.

 

Watch the coolant flow in the rad filler with engine revved slightly (open the cap while cold, idle engine to opening temp of the thermostat). This will tell you if you have normal flow rate. If flow is low, suspect the thermostat, its stuck closed or partially closed. If flow is ok, then you probably have debris, like a sucked up plastic bag stuck on the front of the radiator. Check the fins on the a/c condenser, they could be damaged causing low air flow. Push on the spoiler to make sure it isn't cracked and folding back when you are underway. Another experiment is to remove the thermostat, you should see low coolant temps and long warm up times. Rev the engine at operating temp and watch the upper and lower rad hoses to see if they are collapsing under high coolant flow. Collapsed hoses restrict coolant flow. If you experienced correct coolant temps with the same setup, then you should see them now, and when you don't, something is preventing heat transfer, either low coolant flow, or low air flow through the radiator.

 

We always leave the cap off until the thermastat opens, then one of us holds the RPM at 1500-1700 to pack the coolant in.


I may pull the intercooler and radiator tomorrow but I have a hard time understanding what could have changed in the three days the car was in my shop while we did the heads on it.
Something sure did.

No collapsed hoses, the infrared at the head is showing very close to the close temps to the ECM temps. we went in under generic to see the inputs, but it is the same as vehicle specific so it is not running off a map.

It is going into closed loop and all the numbers look good except for the temps.

 

We have also changed the water pump and three thermastats since we did the heads.

 

Put me down for debris stuck in front of the radiator.

 

I so hope you are right, that puppy is coming out in the AM.
I have to check off everything that it could be before I say
LS1

 

What head gaskets are you using? Last June when I freshened up my motor I used stock GM L98 gaskets. I noticed when I put them on the holes in the gasket that let water pass between the head and the block were very small compared to the Felpros. I am convinced this is why my car is running hotter than ever. Actually saw 245* one hot July day. I have a fear of traffic jams. Its been over 10k miles and still good, but I am seriously thinking about swapping them out.

 

Get a laser read of the temps at the radiator inpipe and outpipe, and also at the heater core in and out.

If ya' think you got too much squeeze in the holes, back the timing off a degree or two, and see what effect that has. 6 isn't much advance, but your options list isn't much either...

 

I am running the FelPro 1003.

 

The Temps at the Rad are mild, the highest I have seen was 170 on the inlet and about 130 on the outlet.

 

One of the guys that I trust on C4 issues has told me to put more advance in it, like maybe go up to ten BTDC.

I am going to fix this one way or the other.

 

Going back together with it now, there were a few leaves in between the condensor and the rad, but not much at all, we did clean everything out.

I should know here in a bit.

 

Based on this statement and all the other things you have checked and changed, it just about has to be in the gaskets, either the head gaskets or the intake gaskets. This post indicates an error during reassembly, either a defective or a mis installed gasket. Whatever the problem is, it isn't the .008" surfacing cut.

RACE ON!!!

 

That is the way I am leaning, the FelPro 1010's that were in there before matched up with the 1003's
and they were put in with the up, up.

I am still thinking maybe the intake gaskets somehow with the revised back coolant ports.

 

Since I am often plagued by "the last thing I did is the reason the next thing is broken" I would tend to agree that something with a gasket somewhere is the root of your problem. However, you don't say whether this is something you're seeing at idle or whether it's continuing to run hot at cruise. If it's at idle, I would use my scanner to verify that the CTS signal is showing ambient after the motor has sat overnight and that the main fan kicks on at 226 with the a/c off. While your at it, you might check fuel delivery too - most richen up when they get too hot. I'd also take a look at the fan shroud and make sure nothing got broken while the heads were off. If it's at cruise, you might take that temp gun and get a read at each head pipe. That will tell you if it's isolated to a particular cylinder. And finally, I'd verify the accuracy of the Display. Seems unusual to see a 12 degree difference (most seem to have no more than a 5 degree difference). Disconnect the harness from the gage sender and verify that the Display shows LO. Ground it and it should show something around 300. I'd guess that your Display is accurate and that you have either a mispositioned/faulty head gasket or a faulty CTS/ECM.

 

It will overheat at idle or at cruise.
New CTS and temp sender.

I have looked at the raw data going into the ECM and it seems to agree with my IR temp gun.

Fan shroud is good and sealed.

Fan is coming on at about 224-226 at the ECM (not on a map)

The fuel delivery seems to be good looking at the O2 outputs.

As soon as I get it running I will check the cylinders to see if one is running lean.

I will check the display, not sure what exact temp I should see with it grounded.

Can you elaborate more on the possibility of a bad ECM?

 

I also have a Inovate wide band O2 in the car, but the sensor is bad.

I may need to get that going again.

 

Still running hot, got to 241 (ECM) and 259 gauge.

Looks like it is coming apart again.
DAMN

 

As a last effort, change your radiator cap. Mine was running around the temps your seeing and that was the cause.