Slowly overheating in the Deep South

[Mr. Bone]

Hello,

I took a 250 mile trip in my 86' chevy 6.2L G30 with a 3spd tranny during the heat of the day (w/o a load in the van) from New Orleans to Jackson, MS. About 2 hours into the ride the engine overheat light came on and turned on the heater to dissipate some the heat from the engine. It seemed to work. I do not want this to happen again though and am wondering what the ideas are to prevent this? This is a new vehicle for me so all the symptoms and problems i'm writing about are "first time occassions" to me.

thanks

[john8662]

First and foremost, verify that you're completly full of coolant.

Second, it's time to check on the condition of the cooling system. The first thing that always gets replaced is the thermostat. You'll really only want to run a Robershaw thermostat, you can get those from KennedyDiesel.com

To diagnose thermostat problems, just watch the gauge, if you notice rapid swings of the thermostat (gets hot then cools down, then hot, etc.) then it's the thermostat sticking.

If the engine just continues to get hot it could also be the radiator is in need of service. Usually you can look down into the filler neck of the radiator and see how much deposit is on the tubes, if alot, it's time for service.

Driving habits also weigh in for cooling. You've got a 3sp tranny, no overdrive, so the engine will be revving quite high for highway speeds. Knowing how fast the van can drive will take time, but usually 70 is going to be pushing it pretty dern hard w/o overdrive and low back gears.

Just do what I do, watch the temp gauge like a hawk, it'll tell you a lot!

[Diesel Blue]

Coolant (i.e., anti-freeze and water) does break-down over time and should be changed periodically. Try removing some of your coolant and take a look at it in a clear container. If it looks brownish in color or not bright, and/or it hasn't been changed in years, it would probably be a good idea to do a coolant flush and replace it with a fresh 50/50 mix. Besides freeze protection, good coolant will help prevent boil-over and also extend the life of your water pump.

Good Luck,

Alex

[Lightyear]

You might try adding a bottle of WaterWetter when you change coolant. It will help lubricate your water pump, and definitely helps keep the temp down. I ran some in a water-cooled Ducati motorcycle in Phoenix mixed with distilled water only, no coolant, for a track day. It cooled so well, I never went back to 'anti-freeze'.

[ZZ]

I would verify that it has the correct thermostat installed. Sometimes, people put gasser thermostats in. The 6.2L & 6.5L engines uses one that has a spring protruding from the bottom.