96 Gt PI swap Overheating

A couple of things I can think of. If the coolant sensor is not in contact with the coolant, it will read low. This could cause the PCM to not call for fan when it is needed.

The SOHC engine will self purge traped air after a few full heat/cool down cycles. The DOHC and V6 will never completely self purge. So it is vital that the correct re-fill procedures be followed so that there is no traped air in the coolant.

Does the car over heat with the AC on? Does the fan run on high speed with the AC on? Have you confirmed that the low speed fan works?

Consider renting a coolant system pressure tester from your local autoparts store. A full pressure test may pinpoint an internal coolant leak within the engine.

There are also inexpensive kits available to test for hydro-carbons in the coolant (possible head gasket leak).

Did you have the car re-tuned for the larger injectors?

Check the exhaust system for clogged cats.

bro123450:

Air trapped in the system, as Mr. Burns alluded to, can cause the boil-over. Wearing gloves and with the engine hot and running, massage the upper hose to move air out of the intake. It sounds weird but it really helps.

Chris

pi swap=higher compression=warmer temps, but however it should run half way. i to am having a cooling problem, its been like this for 4yrs now, but its a little worse now with the pi motor installed. ive tried everything almost known to man (new fan motor, different temp t-stats flushing it before summer gets etc.). im off tomorrow so i may pull the rad, flush it, and the system again but im gonna check for debree in the fins. im crossing my fingers to maybe find something i over looked. i dont know how you did yours but my temp sensor is in the drvers head on my engine as it was from the factory for 2004 and up.

bro123450 said:

Is cap off when you massage radiator hose?

Click to expand...

How many full heat/cool cycles has the car gone through with the radiatior cap closed? More than 4-5? If so, for the SOHC will self purge any air trapped in the cross over (if the system is air tight).

The upper radiator hose trick works right after the radiator has been filled. Its done with the system closed, engine running.

For the SHOC after 4-5 heat/cool cycles IF there is still air trapped in the cross over, it's coming from an internal leak. Examples of air sources are leaking gaskets, leaking head gaskets, or cracked block.

If you really want to fix this, some tests will need to be done to rule out the usual causes of overheating.

What is the condition of the anti-freeze? What is percentage of coolant?
Is the radiator cap holding enough pressure?

>>Engine overheats
1. Retarded spark or spark timed late
2. Defective water circulation
3. Defective oil circulation
4. Thin oil
5. Lean Mixture
6. Camshaft out of time
7. Idling engine too long
8. Running air cooled engine on ground too long
9. Insufficient oil cooling
10. Insufficient oil supply
11. Running engine with radiator or cowling shutters closed
12. Excessive carbon
13. Engine improperly cowled
14. Overheated bearing
15. Tight bearings or pistons out of line

The above list is for an aircraft engine but except for the air cooled part, the list works. Some of the items are less likely to apply because timing is not normally adjustable. Additional items include: Blocked exhaust, Dirty radiator, stuck t-stat, fan not working. Many have already been ruled out.

If this were my car, I would test the coolant percent and confirm the radiator pressure cap. If the coolant percent is not correct, or the pressure too low, it could boil over and nothing really be wrong. Does the top radiator hose get rock hard? If so, the pressure cap is most likely OK.

Next use an ODB2 scanner to confirm the actual temperature of the engine. Next monitor the fan speed as the temperature goes up. Confirm that when the PCM calls for fan, the fan actually runs.

The temperature needs to be confirmed to know that the engine is really over heating. This also gives a way to cross check the two temperature sensors that your car has.

If everything else has been ruled out, consider that it could be the untuned larger fuel injectors. This is going to cause the engine to run chronically rich. Normally, running rich is not associated with over heating.

bro123450:

"fast97gt" made a good point and jolted my memory. Run a search about the '96 radiator because I think there was a TSB about it. It could be the '97. In either case, the engine was touchy about overheating.

Mr. Burns:

Another excellent post. Thank you!

Chris


edit

Here you go:

http://www.stangnet.com/mustang-forums/770115-96-gt-running-hot.html

http://www.stangnet.com/mustang-forums/719912-what-special-about-96-gt-cobra-radiators.html

Looks like you need to upgrade to a later model year radiator and fan.

end of edit