I have an 88 B250 that runs at normal temp when running but when I turn it off the temp gauge gets very close to the high mark. It comes down pretty quickly after I restart but I'm afraid the high temp is stressing the system.

I changed a couple of worn hoses today. I flushed the system with vinegar. Added a 50/50 mix to the system. I checked the thermostat and it looks good.

Is there a fan that should come on after shut down?

What should I do next?

Thanks much.

 

The ultra high temp reading after stopping a full temp engine then restarting a few minutes later is completely normal. It's Called heat soak.

Without the water pump circulating the coolant, the hottest coolant, congregates where the 1 wire temp sender takes it's reading. That is why the gauge drops to the normal range so quickly after restart

 

Thanks for the quick reply.

But, I have a 1977 Dodge Jamboree RV and a 2000 Jetta and a 1967 Islander sailboat, with an Atomic 4 30 hp engine, and they don't do that... not to my knowledge at least.

It freaks me out though. Are you saying I shouldn't worry about it?

Thanks again.

 

Mine has been doing it for the last 10 years. I replaced my whole cooling system last fall.

Temp gauges on newer vehicles are barely relevant. The manufacturers do not want people wigging out over temp gauge needle fluctuations so they dumbed them down. My uncles Cadilliac says it is at full temp by the time he gets to the end of the street, 100 yards away. This is impossible.

Be glad your van can detect and display 15 degree coolant temp differences and worry about other things

 

Thanks, it does give me peace of mind to know that. Appreciate the help.