The Stovebolt Site Forums The Shop Area Engine Shop Engine Temp? Non mechanical geek needs help.

I have a '51 1/2 ton, with a '58 235ci engine.
Last year I put a new thermostat in it (opens at 183 degrees) , since the original issue one didnt register on the gauge. All was fine, running between 180 (the middle point on my temp gauge) and 185..just past center.
This year I found it running hot..spiking to 200 degrees.

So I had a new short shaft water pump put in (classic Parts, aka"Chevy Duty") and my radiator refurbished and checked out by a radiator shop. New hoses of course. Its been relatively cool here, in the 60's low 70's, and the engine is running between 185 and I'd guess 190+. When I turn off the ignition, the temperature climbs to the 220 point, but comes down immediately when i start up and drive.

So... my question is this:
Is the temp I am running (185-190+ degrees) right for this engine? and is it normal for the temp gauge to go way up when I turn off the engine?

If not...what do I do next?

Thanks

Bart,

It sounds like you installed a 180&deg thermostat which would be fine for that engine. When you turn the motor off and the coolant stops circulating, it's normal for a mechanical gauge to climb. Hopefully the shop did more than paint the radiator black. At the very least it should have been boiled or reverse pressure flushed. If you can maintain a engine temperature close to the rating of the thermostat, all is well. If you are going to get real serious about the figures, you will need a accurate thermometer you can stick in the radiator filler and get a true picture of the coolant temperature.

Stuart

Running a 190 thermostat with a 17 psi cap. It some times gets to 215 but the electric fans get it back to 195 ok. NO PROBLEMS

Thanks guys.

I actually watched the radiator guy resolder the drain plug section and the water outlet pipe which rusted out. He pressure flushed and tested for leaks, and put in a new overflow tube which was broken. Says it looked real good for an oldie.

He also suggested that old trucks/cars like mine should use a 7 lb radiator cap...and actually gave me one. Is 7 lbs not right?

So..if i'm hearing you guys right, I should quit obesessing when the needle hits 195. If thats so, I will sleep well tonight.

Bart,

If the needle hits 195&deg as you're driving down the road, keep worrying. I think with a properly tuned system, 15&deg over the thermostat rating is too much. This doesn't count if you're climbing a steep hill with two cords of wood in back of your bolt!

Stuart

darn it atomarc!! I was hoping I didnt hear that.

could the thermostat have gone bad in as little as a few months driving? I mean, what else is there to change / fix after the waterpump and radiator?

Bart,

Your radiator shop did a good job on the obvious outside stuff and it sounds like they know their business. They must have looked into the top tank and made sure the tubes weren't scaled near closed...right! This whole deal is moot until you put your wife's candy thermometer in the filler neck and verify what the dash gauge is telling you. Don't succumb to a infrared point and shoot...use the real deal!

Stuart

Thanks, atomarc...i'lldo that!!

what your saying is with any luck the gauge is just reading a bit higher than the actual temperature.

I have an electronic meat thermometer I can use.
I will report back.

regards,

Stuart,

I checked out the temp using both the electronic meat thermometer and a laser thermometer. When the needle on the gauge is past the center line 180 degree mark, well onto the "0" of the "180" number, both read no hotter than 185 degrees!
I had thought that it being at that spot on the gauge indicated 190+. OOps! My mistake.


The anti-freeze temp was actually a somewhat cooler (like 177 degrees) than the radiator reading of 185, probably owing to it being taken right at the radiator filler opening.


My mechanic says with a 180 thermostat that 185 is just fine. and that if it gets to 190 momentarily while driving hard, that the time lag between the thermostat opening cool down and the gauge response can allow that to happen on old model pumps which dont move the volume of water like modern ones do, etc.

Stuart, what's the verdict? Am I in the clear, or is there more for me to obsess about?

Thanks,
Bart

oh, by the way: Naturally the reading i got was at idle with engine running after I drove around a while.
While driving it does go lower than the guage reading i discribed...fluctuating between exactly the 180 mark, to what I now know is the 185 mark.

I also noted that when I turn the engine off, and the needle goes to 220 degrees, that nowhere on the engine or radiator can I register such a high temp...except on the exhaust manifold.

This sounds right yes?

I tihnk it is fine, it behaves exactly like mine, it will spike to almost 200 degress between the thermostat opening and the cooler water getting to the sender.

When the thermostat opens it will take, oh, about 30 seconds for the water that has started circulating through the radiator to get back to the sender and then cool it back down.

Bart,

Asilverblazer summed it up...all is well in NH. Good job with the thermometers.

Stuart

Stuart, Asilver,

You made me a happy guy!! :-)
Thanks for your expertice, experience and support. Much appreciated.

Now..if you ever need gun advise, I'm your man!

Thanks so very much.
Bart

a post script to this thread, and a final bit of irony.

Naturally, I've been obssesing about that temp gauge and how it reads. I found myself watching it as much as i watched the road. So as i was driving back home from the post office I thought to myself how much easier things were before I put in that new temp gauge and functioning thermostate last year.

30 seconds later I loooked at the gauge...the needle was GONE... fell right off the dial and is resting somewhere inside the instrument cluster.

Good. I wont be replacing it.

But now I'm wondering if I put in a new water pump, and had the radiator refurbished and spent a few hundred dollars in parts and labor just because the gauge was malfunctioning.

Ah, what the heck.

Bart,

As my old friend was heard to say..."sometimes you eat the bear, and sometimes the bear eats you".


Stuart

Heheheh...indeed !!