I have a 1990 4 dr lifted, 33's etc...

When I wheel it hard the engine starts to overheat

I removed the stock engine fan and replaced it with a electric puller fan, (after the 3" body lift it did'nt fit anymore). around town its ok even 95 degrees with the a/c on.
I can't put a bigger fan in----will a 180 deg thermostat help?

I use cool it with the coolant and the entire cooling system is in perfect cond. <img src="/forums/images/graemlins/confused.gif" alt="" />

What size fan? Is it directly on the core, or did you fab a shroud? Lack of low speed airflow appears to be the most likely culprit to me, if everything else is as you say, perfect. A 180 t-stat may be a temp fix.

Too much coolant (over 50/50) will actually cause overheating. An engine with the prpoer amount of coolant ratio and the correct cap will be good to about 256'F as the coolant and pressure increase the boiling point over the 212'F boiling point of water. A 180'F thermostat could help as long as your engine gets to the correct operating temperature and maintains it during all 4 seasons.

Sounds like coolant concentration/dilution is in line. Given the symptoms, it sounds more like an airflow issue.

Review this thread and this thread. Much of it is for a 2.6, but is still applicable.

Basically, a lower t-stat, hood louvers, extra cooling fans, etc, are all well and good, but they are just band-aids on an underlying problem. Yes, I have all of those, but since my cooling system is in good working order, they allow my engine to run extra cool under harsh conditions (such as low-speed crawling on a hot day). Look through these threads to see what may be of issue.

A lower t-stat won't keep you from overheating. It basically may let your engine run cooler under normal conditions or may allow you more time to catch an overheat sooner, but if you t-stat opens, it just opens. It won't keep the heat from climbing if something is amiss with your cooling system.

I put a 180 degree thermostat in my '89 V6 last February. It runs fine under normal conditions -- I haven't wheeled mine so I can't speak to that. The engine definitely runs cooler. The gauge shows about three needle-widths above the mark, and it used to read just slightly under 1/2. Some thought I might experience a drop in gas mileage, or problems causing the ECU to run open-loop, gas mileage is as good as before, and it's sure nice not to feel like I have to watch the gauge like a hawk in warm weather.

Eric W.

Has the radiator been rodded?

If the cooling system is in good condition, it's likely an airflow issue.

If you've ever mudded your rig, make sure you don't have mud build up between the radiator fins.

Also make sure you're not running too rich. If you are (my understanding is) you'll run hotter.