replacing thermostat

hello

i was reading the previous post about no thermostat and was thinking... this past summer i noticed that my thermostat never expanded when the engine warmed up, so i tried to adjust the bracket attached to the engine case and ending up rounding the bolt. after failing there i thought i'd remove the bolt under the thermostat, but instead it broke off. so now the thermosat is at the upper part of the bracket. any ideas on how to remove the rounded bolt and thermostat bracket without messing the stud on the engine case. also how hard is it to repace the thermostat connecting rod with the engine still installed. oh by the way i have a 75 standard bug

-dana

Reply to
Dana & Becky
Loading thread data ...

For getting the rounded off bolt out, try grabbing the rounded of bolt with a Vise Grips, after possibly heating the bolt/thermostat with a torch and/or cold soakings with WD40. All usual ways of removing a impossibly siezed bolt, yano? (PS: I've rarely found those drill into and screw in a bolt extractor to actually work as designed. More often, you screw one in and break it off trying to get the siezed bolt out, leaving something harder than any drill bit you own in the damn bolt!)

And yes, if you screw up the stud in the engine case, it can be bad news! Not irreparable, but messy. (Been there, done that!)

As for replacing the thermostat operating rod, yeah, you can do it without removing the engine, but you gotta remove the fan housing, which can be done if you remove the engine lid hinge mounts too. Ick! And just about everything else from the engine too, like the gen/alt, the carb (is a '75 FI?), etc. In short, it's much easier to do with the engine out of the car, and you're peeling it apart anyway. (Been there, done that too!)

Reply to
John Kuthe

Next time, check the operation of your thermostat with a hair dryer. Give the thermostat a blast of hot air and see what happens. Even if the rod or the connecting lever is the problem, you should see a noticable expanding on one side of the thermostat (as it tries to expand).

Reply to
Luft Gek?hlt

Not sure a hairdryer gets hot enough. I think these thermostats expand at either 80º or 90º centigrade. I generally use a propane torch.

Max

Reply to
Max Welton

Reply to
Ilambert

Actually, no.

Bench testing is certainly sufficient for testing just the thermostat. But frankly, I can tell if the thermostat itself is good just by looking at it.

If you wish to see the rod move and the flaps open, the test has to be done with everything in its proper place on the engine.

I generally hold the torch a good 6-8" away from the thermostat. The heat can be directed onto the thermostat pretty easily without getting anything nearby hot. Have the fire extinguisher within reach and don't attempt this on a leaky engine.

Am I recommending that everyone do it the way I do? Certainly not.

Try this: Take a known good thermostat and heat it up with a hair-dryer and see if it expands. If it does, then your dryer generates enough heat. And you've read the above for nothing.

If not, that hair dryer cannot tell you if the thermostat is good or not.

Max

Reply to
Max Welton

there are two "standard" temps for the thermostats: 65-70 C used on carb equipped cars and 80-85C used on later fuel injected engines...

------------------- Chris Perdue

*All opinions are those of the author of this post* "Sometimes you're the windshield, sometimes you're the bug"
formatting link
reply take your PANTS off
Reply to
Chris Perdue

I have never had a problem getting the thermostat to open with heat produced by a hair dryer. Although it might take a minute or so to get the thermostat hot enough.

Reply to
Luft Gek?hlt

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.