Head Gasket Scare! ... '99 3.8l

[12Ounce]

Trouble comes in bunches! '99 SEL 3.8l engine. 255k miles total. 40k miles since engine overhaul. 500 miles since steering rack replacement.

The thermostat has been in a "failing mode" for some months now ... engine slow to come up to temp in the mornings ... i.e., the thermostat was staying open too much.

Luckily I notice the exceptionally strong scent of coolant one morning ... over 40 miles from home. Checked the reservoir ... empty! Bought anti-freeze and refilled. After a few miles, smelled coolant ... reservoir empty again ... engine area covered in coolant! This time, after refilling, watched reservoir while engine idling ... after a few minutes, the coolant swelled, bubbled and "boiled" out of reservoir. Head Gasket, I thought! Watchful of the temp indicator, I never saw the temp get very high ... but every 2 - 3 miles, I had to stop and refill the reservoir with any water I could find. It took me some two dozen gallons to make it back home.

I was heartsunk about the condition of the engine ... but luckily thought I'd better make sure the problem wasn't a thermostat that somehow had suddenly decided to stick "closed". I removed the thermostat as a test. Now the temp would never rise to normal ... but, at least the coolant was no longer boiling away! Mystery solved ... bad thermostat!

New thermostat ... no more head gasket fears!

[northern piper]

I love that kind of fix! Congrats! I know if it was me what I'd be looking at!!

[garync1]

Great news.. But there is one thing I will say.. All thermostats are not the same. Guy I know at napa brought out three types of thermostats for the same car.. The most expensive one was heaver than the med price one and the cheapest was the lightest of them all.. So If I have to pay 20.00 for the best thermostat I will do it.. The spring and all the parts on it are better than the cheaper ones and most likely will last years longer if not for the life of the car.. BTW the cheapest was 12.00 2nd one was 15.00 and the best one being also the heaviest was 20.00 bucks.. Those were NAPA prices.. I have bought a few from Advance for about 6 to 12 bucks but you know its funny I ended up replacing them again a few years later... Now I know why.. So parts like that along with starter seloniods for older cars I get from NAPA.. Just better..

[12Ounce]

You remind me ... I did not comment on the thermostat itself. The one that failed was a Motorcraft. I'm pretty sure I replaced it with the engine rebuild ... 40k, or so, miles ago. I did no testing on the thermostat ... but it "looked" OK ... clean and bright. The coolant passages in the thermostat housing also were very clean.

The replacement thermostat I got from AutoZone. Very different design and construction. Heavier and larger ... but fit in housing OK. Made in Israel. 195 deg. Brings engine temp up quickly and levels off at the expected reading.

TIP: I also want to comment on the thermostat gasket the AutoZone person sold to me. A hi-tech two-component plastic one from Felpro. Looks similar in style of design to the lower intake manifold gasket. About $9 instead of the $1 cardboard model. But I expect this new one to be reusable and not adher to the metal surfaces as time goes by. If so, money well spent! I'm sure Felpro will not include this one in any engine gasket set ... we'll always have to pay extra for it.