91 safari rwd does fine in town but not on long drives

[Derek939]

So I got a 91 safari from the original owner. Has 151k on it. I've put a new thermostat and fan clutch on it. When driving around town it does ok the temp stays below or right in between the 2nd and 3rd bar. But if I turn my air conditioning on the climbs into the middle of the 3rd bar. Also on long drives without the Ac on it does the same thing. I haven't let it go higher because I usually crank the heat on just to play it safe. Is this normal? Where does everyone else's temp gauge sit at? I have a 91 Astro that never climbs over the 2nd bar. Does anyone have any tips or ideas on what I should do next?

Thanks!

[6spd_monte]

It could be that the radiator is a bit dirty inside, maybe not transferring heat as efficiently as it used to. The factory thermostat should be 195 degrees I believe. My '87 would always run hotter than I was comfortable with so I replaced it with a 180 degree thermostat, now it stays nice and cool, usually just reaching the middle of the gauge.

Another thing to check is to be sure the air is actually going through the radiator like it's supposed to. Make sure the fan shroud is installed correctly, sung against the radiator. Also there should be a heavy duty black plastic piece under the core support that covers the gap between the core support and the front steel panel (the steel panel that you can see just below the grille and extends down behind the bumper). If this piece is missing then air passing through the grille could just flow down and under the vehicle instead of going through the radiator. Also, when you're stopped the fan clutch can pull hot air from under the vehicle back up through the radiator if this piece is missing.

For 1987 it's #20 in this diagram:
http://www.genmotorinfo.com/Picture.asp ... 28TM01-001

In the 1991 diagram I think it's #17:
http://www.genmotorinfo.com/Picture.asp ... 22TM01-403

The '90-'94 radiator mounting is a bit different than mine, but #17 looks like the part I'm talking about.

[Kidhauler]

You might have gotten the wrong fan. This happpend to Canadavan a few years ago and the fan was pushing air out the front instead of pulling in.

At speed it would balance the pressure and the van would over heat but in town it was fine.

[LiftedAWDAstro]

If the fan is mounted to the new clutch correctly, I would look at the radiator being plugged internally. Getting a new one locally or off E-bay is pretty cheap so it would be worthwhile to replace the 21 year old one anyway.