Stuck T stat?? Overheats then cools

[l3lue]

Car still has stock radiator (I know it needs to replaced and will be replacing it shortly) Radiator is leaking so will be replacing that, but took out for a drive today and noticed temps were normally around 185-189, then as i was driving looked down and it was 245! then I watched it quickly drop back down to 185, then after a few minutes it quickly climbed back to 245 then dropped back down again...Not driving it for extended period of times until I get this figured out, I am told the car has a 160* tstat in it, do I need to replace this? Thinking about replacing

Radiator
Tstat and both radiator hoses. -- any suggestions?

 

[mr84ss]

What temp is your fan coming on?

 

[1KWIKSIX]

I wouldn't be driving it at all until you replace those items.
Yes to all the above. Plus give it a good flush to get rid of all the crud built up over the years.
After filing with fresh glycol / water solution, add a bottle of RMI-25. You should be good to go then!

 

[l3lue]

What temp is your fan coming on?

not sure, but the car has a fan override switch and I turned that on so fan was running whole time once I saw it start climbing

 

[mr84ss]

I wouldn't be driving it at all until you replace those items.
Yes to all the above. Plus give it a good flush to get rid of all the crud built up over the years.
After filing with fresh glycol / water solution, add a bottle of RMI-25. You should be good to go then!

What product do you use for a good diy radiator flush on your car? Ive read to use prestone, degreaser,baking soda or vinegar.

 

[1KWIKSIX]

I normally just use plain water. Add a tee fitting with hose thread and cap (prestone) , install it in heater hose line temporarily and turn on the hose. With rad cap off, run the hose until clear water is running thru the system.

 

[mr84ss]

Cool. While were on the subject of coolant. What is a coolant bypass mod? I read it somewhere but they didnt go into any details

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[1986 Buick GX1]

Cool. While were on the subject of coolant. What is a coolant bypass mod? I read it somewhere but they didnt go into any details

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More than likely it's either capping off the coolant hoses that go to the bottom of the throttle body or connecting a hose from one to the other, bypassing the throttle body.
The theory is by not running hot coolant through the throttle body the intake air temp stays cooler.

 

[l3lue]

Rock auto says APDI/PRO 8010683 is a replacement for a turbo regal, has anyone used this?

Also looking at http://buickgn.com/aluminum radiators.htm

any other suggestions? trying to not spend 500+

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