98 Gr Caravan overheating at High Speeds

[Timothee]

My 98 Grand Caravan 3.0 only starts to overheat on 2 occasions
1. When I drive at 60-65mph for 10 minutes (on Highway) or more but once I slow down and go about 45mph it will go back to 3/4 hot

2. When I do city driving with A/C on after about 15 min the gauge will steadily rise to the hot side, but will go back down to 3/4 when I turn the A/C off and drive at a lower speed or stop the vehicle completely.

My coolant is fine good color level is good, during the winter months city driving is fine the thermostat stays at no higher than 3/4 but I can drive all day (as long as I don't hit the highway) with no hick ups.

Any thoughts would be great thanks
Any Thoughts---------

[vipergg]

Originally Posted by Timothee

My 98 Grand Caravan 3.0 only starts to overheat on 2 occasions
1. When I drive at 60-65mph for 10 minutes (on Highway) or more but once I slow down and go about 45mph it will go back to 3/4 hot

2. When I do city driving with A/C on after about 15 min the gauge will steadily rise to the hot side, but will go back down to 3/4 when I turn the A/C off and drive at a lower speed or stop the vehicle completely.

My coolant is fine good color level is good, during the winter months city driving is fine the thermostat stays at no higher than 3/4 but I can drive all day (as long as I don't hit the highway) with no hick ups.

Any thoughts would be great thanks
Any Thoughts---------

You don't indicate whether the fans are working , that would be the first thing to check , if the fans are working it should never overheat unless there is a problem with something like the radiator fan relay which could cause the fans not to come on which was a problem and covered under a recall for this era van . Generally your temp on the dash should be no more than halfway if its running right.

[RIP]

If its not the fans it could be your thermostat is only partially opening and restricting the flow of coolant. $10 and an hour to change it would be a good move. The pump could be going. Thats about $50 and three hours. Worst case is the radiator is clogged up. Hopefully you've been flushing the coolant every other year to prevent this. Thats when I would take it to a rad shop and have a new one put in for about $300. Please let us know what fixes it.