When I’m driving my ‘55 Super 88, the temp gauge settles in on the third mark, the one just before “hot”. It doesn’t matter if it’s 50 degrees or 90 degrees outside. When I come to a stop, it cools back to the middle mark. Does this seem normal? It has never reaches “hot” and the car runs normally. It has the stock radiator, I’m just trying to get others input. Thanks in advance….Bob R.

 

Is this something that just started? When was the last time you checked your engine tune?

 

Ive had the car for 3 years and it’s always done this. I had it tuned up 2 years ago and don’t put many miles on her yearly. It runs well overall. I don’t think these cars had radiator shrouds and thought about adding one.

 

It sounds like you may have a 195 degree thermostat installed.
Not to worry, as long as it doesn't go to "Hot".

These cars originally had 180 degree thermostats, but a 195 will work just as well.
Make sure the rubber seal on the radiator cap is in good condition.

 

195 thermostat would not explain why the temp goes up when the car is moving and drops at idle. I'm thinking something is wrong with timing or the carb is running lean. Is the radiator clean both inside and out? I do agree that the temps are probably nothing to worry about damage wise.

 

The rad is clean on the outside, no debris etc. It was flushed and filled with fresh antifreeze 2 years ago when the tune up was done. It even close to 1000 miles since that all was done.

 

I'd suggest getting an Infrared thermometer to take the guess work out of what a gauge is doing. Put a piece of black tape on everything you shoot and post the results. Shoot the thermostat housing, upper and lower radiator hoses and various points in the radiator looking for cold/blocked spots.

Probably and hopefully there isn't a problem.

 

Adding my two cents. We're referencing a 70 yr. old analog/mechanical display? This is the type of mechanical gauge & attendant needle which uses a capillary tube? I'd sorta suspect the (1) line tubing from the sender to the gauge, (2) the sensor probe, or (maybe) the capillary tube itself?

 

I’ll give that a try, thanks!

 

As opposed to an electronic gauge/sensor? I’ll have to checkout what i have.

 

Yes. Simply theorizing whether an issue might exist at the gauge, probe &/or tubing which feeds the capillary tube (if it has one).

https://www.onallcylinders.com/2022/...-to-test-them/

 

Borrow the kitchen thermometer, check the temp at the radiator fill point, running and hot. Don't get scalded. If it checks close to thermostat temp you are good. The electric temp gauge sending units experienced various aging failures since the beginning of electric temp gauges up to the time of idiot lights - much more so with 6V then 12V but still a problem. Every NAPA had the 12V unit with black plastic insulator in stock until recently, not so much today. Not hard to find through restoration suppliers if needed. Good Luck~

EDIT - Actually not so easy to find anymore. The Pontiac supplier I checked who had 6 and 12 sending units no longer seems to list them. Eckler's maybe for 1956 Corvette but has a stud not a threaded post. Easy to thread that if last resort. $80

 

Lots of great input, thanks to all. I’ll have to start tearing into her and see just what I’m working with…

 

When I had my 54, it ran really warm after I installed the AC. I won't bore you with all the things I tried that did not work. What I wound up doing was installing an aluminum radiator, a generic shroud from Speedway, a six blade fan and a pusher electric fan that I had set to come on at 180°. The radiator was for a 68 Dodge Coronet which was the correct width (24" I think) and had the flanges on the sides. It was a little short so I made an air damn to go under it so all the air went through the radiator. I had to cut the bottom hose off a little and use a spacer in it. After all that, it ran cool even in a Texas summer. I also ran a Stewart Warner temp gauge under the dash.

 

I was thinking about an aluminum rad and adding a fan shroud. I think I’ll try to determine if it’s a bad sensor and/or temp gauge first. Thanks for your input!

 

You've had the car three years, the gauge has always done this, and you've never had a problem. Why are you trying to fix what ain't broken? Put the tools down, get your wife, and go for a ride to the ice cream stand without once looking at the temperature gauge..


Here's some recommended reading for you.

https://classicoldsmobile.com/forums...-carol-181592/

 

X 2
Those gauges were not precisely calibrated back then and were "good enough". You can pick some arbitrary number and make modifications to meet a certain number. Spend a lot of money and call it an "Upgrade" to justify it.
Just make sure things are correct and enjoy it.

 

Jaunty75, I read from your required reading list…..fricking hilarious !! Ok,ok…..let me check the cap and make sure it’s in good shape and I’ll see where it goes from there.

 

I have EXACT the same issue with my 55 Super 88.When I drive for a while and the engine warms up, the temperature goes up until 75 % of the temp gauge. When I have to stop at a red light for example, the temperature drops to 50 %. When driving again, it will raise again. And so on....

I think the belt to the water pump is too loose. Under force of driving and rpm it slips and the pump circulates the water less. At idle, the belt rotates slower and has grip with the water pump's pulley and it can cool down proper. So I think we have to tighten the belt, correct? And of course check it for wear.

 

The belt may also be old and "glazed",
If the working surface of the belt appears shiny, then it's time for a new belt.

 

A slipping belt will cause the temperature of the pulley on which it slips to increase dramatically due to the sliding friction. The pulley on which it is thought to be slipping can be confirmed/ruled out with an IR thermometer.

 

Chris, thank you for your response! I thought I was losing my mind.....since my original post I've:
Changed the radiator cap, new thermostat, new temp sensor with new Bosch gauge. This led to no change, the car runs at about 200 degrees when driving. So as of yesterday I added a new water pump, aluminum rad, new upper and lower hoses, universal fan shroud and a 6 blade fan and burped the system. Net result....wait for it...NO CHANGE...still operated at 200 degrees. So its gonna get driven, if the damn thing explodes, its staying along the side of the road with the key in it and a note saying whoever finds it can have it!! Sick and damn tired of messing with it.

 

You're chasing a phantom here. There's nothing wrong with 200 degrees. Your engine is happy to run at that temperature all day long. It could run all day at 220 with no problems.

People are so obsessed with engine temperatures and panic if they're a degree or two above some fictitious "standard."

Has anyone ever noticed that factory service manuals do NOT mention what a "proper" engine operating temperature should be? That's because there isn't one.

I put a temperature gauge on my '73 Delta 88 with a 350. It sits at about 210 all day long. Car runs fine.

 

What will explode ? Why do you think it will explode ? If you had been born and old enough to drive these cars "back in the day", you might realize how they operated normally. The 324 was manufactured in 1954, 55, 56. They probably produced hundreds of thousands or even millions of those engines. They were probably tested on Arizona test track/proving grounds.
After all the money and time spent to achieve your arbitrary number, what have you learned ?

I think if people had driven these cars 70 years ago, they would have a different opinion.

 

Which would have been what?

That they had to obsess about their engine's temperature? That they had to try to control it to the nearest nanodegree? That they had to keep throwing new parts at it, as Bobs55 has done, in an attempt to fix what wasn't broken?

I think that people driving these cars when new or nearly new paid little attention to the temperature gauge, if the car had one at all, and just drove and enjoyed their cars.

 

That people would have driven the cars and not obsessed over arbitrary coolant temp range. I owned a 55 Olds 88 for a couple years and drove it everywhere. Once I drove it to Wichita, Kansas, picked up a Singer Industrial sewing machine and drove right back to Waterloo, Iowa. A 1,000 mile round trip without a problem.

 

This is the gist of what I said. In response to my earlier comment, which you quoted, you said that people 70 years ago "would have had a different opinion." I think what you meant to say is that people 70 years ago would have had the SAME opinion.

 

They would have the same opinion as you and I, not the opinion of the current one. Actually, I was agreeing with you.

I am sure Jeg's and Summit sell a lot of aluminum radiators to people that don't need them. If a person thinks they need something, Jeg's and Summit are more than willing to sell it. If the part doesn't do what the purchaser had hoped, they can say, "sorry, but thats what you wanted and ordered".

 

Today I changed the thermostat, now the temp gauge stays constant a bit over half. I‘d say I solved the issue.

 

Cool!

 

What did you change it to? Same rating, or one of a different temperature?

 

I installed a 160 degree thermostat. I don't know the rating of the old one, I couldn't find anything written on it.

 

Thanks.