Hello just had my cooling system flushed on my 88 with the 305. It now runs hotter. Generally above 220 sometimes closer to the next mark. Not into the red at this point. Always felt it ran low before the flush, and it usually sat at the line between 100 and 220. Once I’m up to a higher speed it comes down somewhat closer to 220, but in stop and go it’s usually between the 220 and the next line up. The old coolant was very rusty and discolored so I’m not sure when it was last changed before today. Thanks for any ideas!

 

How did you perform the flush? Did you have to remove the thermostat?

 

No the thermostat was not removed. That’s another issue, one of the bolts to remove the thermostat has the head broken off.That will also need to be addressed.

 

If the thermostat is in its original position, then either you pushed debris into the radiator and created a clog or you have an air pocket. Easiest way to purge an air pocket is Jack the front end up and run the engine with the cap off until the thermostat opens.
Less likely, but still possible if you used anything caustic to perform the flush is water pump impeller failure. But typically that will show itself under load , not idle

 

U MUST remove the thermostat to fully flush the cooling system. Remove the rad too & flush it separately. The chev block does flush like a Buick block with the Buick, the when u place the hose in the left bank, old coolant flows out the other bank. With a Chev, it does not only flies back at u. Been there & flushed many cooling systems over the years.

 

Damn you're good Ratfink....