Help Reatta thermostat

[nyyanksdj]

I'm having some over heating problems. I want to replace the thermostat. Is the thermostat located at the end of the hose at the engine, coming from the radiator? I only see one bolt on the cap where the hose connects to the engine. Is the thermostat easy to replace on a 1990 Reatta with the 3800 engine? It could be the fan is not working properly, but I still want to replace the thermostat to see if this is the problem. Any help would be greatly appreciated. Thanks.

[Guest F14CRAZY]

Yup, it's under the elbow with that one bolt. It's pretty easy to do but maybe be difficult to deal with the bolt, and it can be hard to turn, and in a hard to deal with spot.

When picking up a thermostat, ask for a 180 degree one.

[Guest F14CRAZY]

Also, with the one bolt, it may be difficult to get it square when reassembling. Wanna make sure it is.

[padgett]

I find them easy to change. Keep in mind that the water neck seals with an O-ring and the bolt just holds it in place.

The secret is to have an absolutely clean surface both in the manifold and on the water neck. If it is all clean and smooth the O-ring will seal. If not, welllll.

Not much you can do about the manifold but if the water neck is corroded, replace it.

As to installation, the side of the thermostat (I like a STANT Superstat, 180F) that says "to radiator" points up.

Some 3800s have a second rubber washer that goes on top of the thermostat. This is to keep coolant from flowing around the thermostat when it is closed and not to seal the system.

Cover the ring with antiseize before installation and be gentle. If everything is clean and smooth you may be able to just slide the assembly into the manifold by hand. If not press on the flat on the side opposite the bolt with a big screwdriver while screwing in the bolt so it goes in evenly.

Again the seal is the O-ring so a little tilt when you are done won't hurt and the bolt does not have to be very tight, just snugged down.

ps if it is running hot over 50 mph it is not the fan.

[Guest imported_dantm4]

I 2nd the 180 degree stat....mine still runs hot in the summer with the A/C on at a standstill, but is doing only 5 bars instead of 6 if it's below about 75 degrees. (sorry haven't checked the actual temp in a while) I don't recall it being too difficult to change, but it was weird with just the one bolt.

-Dan

90' Black/Tan Coupe

[Blue90]

I am also about to change the thermostat in my 1990 due to running hot. Thanks for all the info. Does the O-ring ever need replacing?

S.

[Guest F14CRAZY]

maybe. But as Padgett said, it's not really important, so I'd just RTV it

[Shelby]

The O-ring is cheap and is the best insurance against a leak.

Use RTV Sparingly, it plugs up water and oil flow.

[Guest F14CRAZY]

What he said

[padgett]

I *always* change the O-ring (have a stack stapled to the wall) and *never* use RTV unless forced. For thermostats, Never-Seize is my preferred lubricant. Secret is not to stop until surfaces are CLEAN.

[Blue90]

My mechanic recommended a 190F thermostat. He said that the engine would run better, be more fuel efficient at the higher temperature.

Comments?

S.

[padgett]

Common mythconception (BTW choice is 180 or 195, not 190). I find that everything under the hood lasts longer with a cool ebgine and I see 30+ mpg at 70 & 179F coolant on the interstate. The magic number where everything starts working is 146F so 180 is plenty even if you experience 0F weather.

The general says 230F is fine but never expected these cars to last this long.