[DCartier]

Recently purchased a 1998 Deville that we believe had been sitting for a while. Overheated within the first 20 miles of driving. We were told there was an internal coolant leak and to try Kseal. Which we did. Car idles at around 215-220 with AC on full blast. However within two miles down the road it is up to 235-245. Highest temp was 248 while sitting in the driveway revving the engine.
No visible leaks or fluid loss. Did get stinky at 248 but no smoke of any sort

Any ideas?
Thanks!
Danielle

 

[MoistCabbage]

The sealant was a BAD idea.

Internal leak = head gaskets. In the case of he Northstar, it's the head boot hole threads ghat fail. Sealants simply won't work, but they WILL cause blockages that are difficult or impossible to remove.

No coolant loss is a good sign. First things to check would be:

- Proper coolant level.

- An inspection of the water pump drive system (it's on the left side of the engine, the pump is driven by the I take can via a belt),

- Is the purge line clear. Do a search for purge line, there are ENDLESS posts on how to check it.

- Are the cooling fans operating. This is only applicable if it's overheating at idle or low speeds.

 

[Ranger]

We were told there was an internal coolant leak and to try Kseal.

Stop taking advice from this person.

If all the things MC mentioned check out OK, it's time for a block test.