Is my Thermostat Sticking?

[borjis]

Much like a jet fighter pilot, I monitor my guages constantly always on the lookout for abnormal conditions (water temp and oil pressure)

I was driving today and noticed that the temp guage was going well beyond "N" for the first time ever. This engine has just over 1,000 miles on a full rebuild and everything during the restoration of the car (completed last year) was replaced.

Now it would get very close to the red zone while driving, when at a traffic light it would quickly move back to N. But when the RPMs went up even a little, it would climb back up again.

Is my thermostat bad/stuck?

I'm seriously considering removing it and running without one as I only drive the car on nice days and only after a proper warm up period.

 

[maynard]

You didn't say what year your car is, so here is a couple of ideas.

If it has an electric fan (as in the rubber bumper cars), it may not be turning on.

If you don't have the electric fan, you have the typical sympton of a partially clogged radiator.

 

[borjis]

1972 MGB.

It's a brand new radiator and both (heater core also) were flushed and pressure tested when the engine was assembled 2 years ago.

I checked the coolant levels before driving today and it was full and the coolant green and clean.

It does have an electric fan but its working well as usual.

Like I said, its a brand new car now with about 1,035 miles on it as of today. This has never happened before.

 

[jlaird]

Agree, would remove the thermostat and see what happens. It will be fine without the thremostat for quite some time. In any case they are cheep.

 

[David_DuBois]

"...when at a traffic light it would quickly move back to N. But when the RPMs went up even a little, it would climb back up again." The fact that the temp indicationclimbs quickly with any increase of RPM would indicate that you have a non operative voltage stabalizer. If the thermostat was stuck, the temperature would not drop when you are waiting for a signal (the temperature doesn't drop that quickly), nor would it climb quickly with a rise in the RPM. Take a look at your fuel gauge and oil pressure gauge (if it is electrically operated) and see if either one of them goes through those silly gyrations with changes in the RPM. If they do,it is a clear sign that the voltage stabalizer is causing problems.
Cheers,

 

[borjis]

David, that is VERY interesting indeed.

My fuel guage was acting funny today as well.

I filled the tank a week ago and the guage went down a little but sometimes it would peg itself at full.

Today it did the same thing, sometimes it would show 1/4 tank but it would be pegged at full again minutes later, I kept wondering why the heck it was doing that.

Oil Guage is mechanical and was operating properly.

The voltage stabilizer (the little box next to the fuseblock right?) is one of the few things that has not been replaced and is the same one the car has had in it for 10 years when I bought it before the restoration.

I was just thinking the other day of replacing it with the new solid state one that Moss sells as the original looks old and not so pretty to look at compared to everything else in the engine compartment.

Anyone else using the new moss solid state voltage stabilizers?

 

[David_DuBois]

The oltage stabalizer is on the forward bulkhead ahead of hte dash and roughly in line with the steering column. Check the ground to the thing before replacing it. It is grounded through the mounting screw, so take the screw out and check that you have bright metal on both the stabalizer and on the bulkhead around the screw hole. If you do need a new stabalizer, the solid state ones will work fine.
Cheers,

 

[borjis]

moss was out of ones for negative ground so I ordered one from victory british.

Interesting it is the box in the bulk head.

Do you know what it is that is mounted next to the fuseblock? (little metal box)

 

[Kimberly]

Can you post a picture of the item next to the fuse box?
What color wires are connected to it?

 

[BoneIdle]

It's probably your stabilizer, but I had similar symptoms when I first put mine on the road. The rear brakes locked up after driving about 50 miles ( lack of use by PO). Sitting at a light was no problem, but as soon as I accelerated, the temp gauge would start climbing. Funny thing: acceleration was a little sluggish, but not so much that you'd suspect the brakes were having problems.The smoke from the rear wheels gave it away, though.