So I finally got around to puttin in the water temp probe for my factory gauges in my Delta 88 (307) and I was cruising today and it's a nice day and the temp got up to about 230. Didn't go above that.

Car runs fine, no smoke, no loss of power etc etc. I'm thinking the gauge may be wrong. I have a another water / oil rallye gauge I can swap in but if its right, is that too hot. No leaks, and dropped a 180* thermo in about a month ago.

Also the "high temp" is still hooked up, no light either!

 

In my opinion, that is too hot. Some engines do run that warm, but they are using hotter thermostats also, since a hotter engine generally means a more efficient engine, to a point. However, with a 180 stat in there, that sounds pretty warm. When is it reaching these temperatures? Slowing down after a high speed cruise, at idle, on the highway?

The "HOT" light likely wont come on until about 265F.

 

That's what I figured. It creeped up to 230 while I was driving in the 50* weather.

So it's either the gauge is wrong, or I'm thinking the radiator.

The guy who owned the car before me replaced the radiator. He claimed to have ordered the correct one, and it just didn't fit correctly. After some research, it's a radiator for an 86-90 Delta 88, the smaller car with the 3800 Gen I engine.

Going to swap the gauge first. Car hasn't overheated and I drove it since April like that, including a 200 mile day which had track time and it was 100 with 95% + humidity here all last July. With a 195 stat, no problems

 

Also is gets to 230 and sits there. In traffic, driving, stopped at a light, idel. Doesn't matter

 

I'd check the gauge and the thermostat first.

If it's a bad radiator or fan, it would keep creeping up under the right conditions, and yours stops dead at 230, like the thermostat is opening there.

First confirm the gauge reading, then swap thermostats and check again.

- Eric

 

Too hot for winter!
Check temp with an IR thermometer if you have one.
I have also had bad stats right out of the box. The one in my '86 is stuck wide open!

You say the car did not overheat before, even with the wrong radiator?

 

I'd test the thermostat also. I assume this engine uses a belt driven fan with a clutch? If the clutch was bad, it would run cool at high speeds and overheat quickly once you slowed down and the air flow decreased.

How are the hoses? No signs of the lower hose collapsing while its running?

If the t-stat is ok and the fan clutch is ok the next thing I would do is pressurize the cooling system (and rad cap) and see if you got a leak anywhere.

 

First, with a 15 psi cap, the coolant won't boil until over 250 deg F. Second, the 307 is the only Olds I've ever owned that had trouble getting all the air out of the cooling system. I've had air pockets cause high gauge readings, so be sure you have the system properly bled.

 

I swapped in the extra gauge pack today and this one went to 220 and stayed there. The way this one operates is better. The oil gauge doesn't bounce around and the water gauge works slowly. What I mean is that it didn't shoot right up like the other one did and didn't drop a bit and then go back up.

I've been wanting an IR thermo for a while, so I'm guessing a trip to Harbor Freight is in the future

What would I measure with the IR? I'm guessing the upper hose.

How do you get all the air out of this system? Uncap the overflow bottle or the radiator?

I know a bouncing temp gauge is a sign of air in the system, but this gauge isn't doing that.

I want to troubleshoot instead of throwing money at it and hope it works

 

Uncap the radiator of the engine while cold. Let it warm up til the t-stat opens so the coolant can circulate. The level in the radiator should drop once any air in the system escapes, keep topping it off if necessary. You should also set the heater to the hot position so the flow valve will open and allow circulation through the heater core as well. Sometimes on the more stubborn engines it is useful to park on a hill so the radiator cap is the highest point in the system, makes it easier for the air to travel there and escape.

Make sure its full, cap it, shut off engine, you're done!

 

^^ OK thanks.

Wasn't too sure of that. Sooo much easier with my Alero, it has a bleeder screw on it

The more I think about it, I'm thinking is could be a t-stat, and it's opening at 205 or 220. When I drove it today and got he 220 reading, That was after stopping at a light and then pulling into my apartment's parking lot, park and idel. Right before I stopped, the needle was maybe right below the 220 mark, You couldn't see any black between the red needle and white line. On a gauge that broad, I'm thinking that was 205 to 215. I remember when I bought the stat, just like all my parts I buy, I checked the part BEFORE I bought it and yes it did say "180" on the stat. Maybe I got a mislabeled one? At $10, I'm not going to cry, too much.

I don't have a fan clutch. The fan turns all the time. My old Delta did the same thing. I'm going to be switching to an eletric fan anyway in the future, but since it's "not needed" right now, it goes on the luxury list

 

Nope, measure on the manifold right next to the water temp sensor!
Everyone should have one of these things - great little tools!

I have burped systems by filling cold, starting engine, heater on, and leave the cap off. Keep filling as it goes down until you are about an inch from the top. When the stat is open, blip the throttle to 2 k for a just a few seconds at a time. Top off and recheck now and then.
This works on my '86 pretty well.

 

Picked it up tonight! Gave me a chance to do a scan tune on the Alero too

OK I'll check it out

 

BUT, since IR thermometers read best from flat black surfaces, the upper hose (once the thermostat has opened) might be the best choice, especially on cars with aluminum intakes.

I'd check it on both and compare.

You can also check both the upper and lower hoses to be sure there is a difference - if they are too close in temperature, it means that the radiator isn't cooling the water.

- Eric

 

I found the hoses to be cooler than the block. I can usually touch them but never the block. I have measured all colors of things with good accuracy, even aluminum surfaces. Never thought there was an issue... Need to look into this

 

I'm surprised you could touch them. I've found the hoses of every car I've had to be too hot to touch after any kind of a good run.

Now I'll have to go experiment with the thermometer when it's a bit warmer out.

I may be wrong...

- Eric

 

IDK I burnt my arm on the upper yesterday

 

I usually touch with my fingers, which are tougher...
Of course none of my engines were running that hot, either.

 

Ok the IR test show the gauge is wrong

With the gauge reading 220
Upper hose 172
Lower hose 149
Temp sensor 167
Gauge sensor 107 (it's in the back of the motor and doubt I got a good read on it)

Dash at 230
Upper hose 185
Lower hose 168
Hi temp sensor 191
Water pump 196

I noticed with the old Delta, one probe was to turn on the fan at 195 (front of mani) and the temp probe at the back of the mani read 197

So if my gauge is showing around 230 and the coolant temp is 191, that means the gauge is off by 40* give or take

Is there a way to get it to read correctly? What does everybody think I my temp findings?

 

Im confused...
Are we still talking about the 307 Delta?
I never heard of a sensor at the rear of the block... Was this custom mounted?
Also, you have had electric fans installed?

Regardless, the IR measurements seem pretty normal for a 180 stat...

 

Two things:

1. I would calibrate the IR thermometer if you are going to use it for absolute (rather than relative) temperature measurements. I calibrated mine with a pot of boiling water.
Try to use a pot, or a surface inside the pot, that is close to flat black (ie: not bright silver, which reflects infrared energy). Boil water in it, keep it boiling. Point meter at black object in boiling water, which will always be 212°F at sea level. Measure temperature a few times, to be sure it's consistent.
Mine turned out to read 5° higher than the actual temperature, so I wrote "Subtract 5°" on the handle to remind myself.

2. I agree that those temperatures correspond to about what you should expect with your thermostat, but remember that the temperature at various points on the outside of the engine may or may not correspond closely to the temperature of the water in the water jacket.
Also, notice that at idle, the water coming out of the radiator is 18-23° cooler than the water going in - you can see the radiator doing its job.

Sounds like you found your problem!

- Eric

 

I put the sensor in the back left corner of the mani. There was a heat controlled vacuum switch in place, so I removed it and bought a probe for a 1980 Delta with these gauges and Put the sensor in there. I had my AutoMeter gauge in that port in my old Delta and I liked it there because it's hidden and out of the way.

So I now know that this gauge is off by 40 degrees so I'll just keep that in mind whenever I drive the car.

How ghetto would've look for me to cover up the 220 with a 180 sticker?

 

Oh and I will calibrate that IR thermometer

 

My 1984 olds delta 88 ran at about 200 with a 195 degree stat. even with the 350 in there now its still about the same 200 degrees when driving. Sounds like you might have cooling problems

 

That's not "Ghetto," it's "Custom!"

- Eric

 

Glad I found this thread. I am having a similiar issue on my Olds Delta 88 Convertible, it has a 2bbl 455. I had driven it from Minnesota to South Carolina and then to Georgia. This spring I decided to put a temp gauge, and I noticed the temp would get hot then cool a bit and go back and forth, so I thought, replace thermostat, I did that and now it runs up and stays there. I am going to get a thermometere from harbor freight and check with help from this post, I will post back, but what are temps i should get on this car?