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I have a 1961 Olds 98, with the 394, 4bbl Rochester carb. I've had it for about 10 years or so, given to me by gramps. It has always run hot and/or overheated. I am wondering if these things just run hot or if I can pinpoint what the deep-rooted issue is. Here is all you need to know, I think:
I replaced the original rad years back, I accidentally hit the radiator with a tranny line running it back up to the front of the car because of a line swap I was doing. It leaked bad and never got it fixed. I simply bought a Champion aluminum one, in hopes it would help. It did not solve the issue.
It runs about 210 -230 and increases, especially on warmer days (here in MN it's about 90 degrees lately). If I hit the freeway, it will cool down to about 195. I can see the temp gauge drop. I installed a temp gauge btw. It won't puke out the overflow hose unless I fill the rad too high, which I have done. The coolant is about 1.5" below the neck of the radiator, cold.
I just flushed the system, lots of rust- colored water. Right now, it is 50/50 mix. Thermostat is a few months old, 180-degree. Rad cap is 15 lb. rated. Upper and lower hoses have the coils in them, no leaks there. Using the original 4 blade fan, but ordered a clutch, and will use a 6 -blade fan I have with the clutch, when it arrives this week.
Car has 97,000 original miles on it. I believe the carb is tuned great, it runs and drives great. Smooth.
Water pump has been replaced, no leaks from it.
Can anyone help me figure this out? What am I missing? Bigger rad? Do these 394's run hot? I feel like these engines ran properly years ago when they came out and that there is an issue I need to figure out.
HELP!
Thanks so much guys, I truly appreciate this. I feel like I am in good hands!
Confirm that if equipped, the heat riser valve in the exhaust manifold is fully open.
Put a well sealed shroud on the radiator so that the air drawn by the fan gets pulled through the radiator, otherwise the fan just swirls the engine compartment hot air around.
Use an infrared thermometer to shoot the radiator for cold spots indicating blockage.
Look at the water pump impeller to see if it rotted away.
I do not believe it has a heat riser. This is from the manual for the vehicle:
"As the engine warms up, hot air from the exhaust manifold is drawn into the thermostatic coil housing (on the carb). The hot air raises the temp and causes the coil to slowly relax its tension allowing the choke valve to move gradually to the full open position."
Or am I missing it completely? It would be on the exhaust manifold?
Another point as I read the manual, it says a 170 degree should be used. Would that make much difference than a 180?
Two different things that operate on the same principle. Yes on the exhaust manifold...good question by the way. 170 would help but remember a properly operating thermostat only controls the minimum temp., it makes the engine reach a minimum temp., the rest of the cooling system rids heat over that minimum. Think of it as as "push pull" balancing situation.
I also read that when draining the system, two plugs on either side of the block should be drained as well as the petcock on the rad. Could there be a lot of buildup that hasnt been drained from the system? The car was sitting in a garage from the mid 90's until 2010, when I took it under my possession. I did see clear water running out when i removed the thermostat, undid the hoses from the rad, and flushed water into the top hose until it came out the bottom end of the water pump outlet. where the lower rad connects to.
Yes there could be build up but it usually isn't that bad. If you are running the car and the system is staying clean then it likely isn't a plugged up block. Attempt to remove the plugs if you can access them but keep the force applied to a reasonable level. If they are seized don't break them off to later find there wasn't a problem.
I honestly think the issue may be insufficient air flow that actually gets through the radiator, that is where a shroud helps. Saying this because it cools when you go down the road which is a good/normal thing.
Ignition timing is set to spec? Running premium fuel?
When you use the infrared thermometer place a piece of black electrical tape on the surface of your target. Also use the IR to thermometer as a confirmation of gauge accuracy.
Will the clutch and fan help? Yes. Are they needed? Not when the car was made so they may mask an issue. I'd try a new and tested before installation thermostat first after tests with the IR thermometer and checking the other items.
All the above are good suggestions. I think 230° is a little warm for that car. The fan shroud should help. If you install one be sure your fan blade is half in and half out of the shroud. I had a 54 Olds that wanted to overheat after I installed AC whether the AC was on or not. I eventually installed an aluminum radiator and a fan shroud with a 6 blade fan and used a pusher electric fan that came on at 180°. Problem solved.
The heat riser valve is located on the drivers side exhaust manifold between the manifold exit and the cross over pipe, should be about an inch thick with a bendix spring and a counterweight. These become stuck in the closed position sending exhaust through the intake to speed up the carb heating process. Make sure this valve is free and not closed, if you can't move the valve shaft then remove the valve plate and remove the valve and plug the shaft holes.
The other thing on these engines is build up around the cylinders in the cooling system. Remove the frost plugs and flush around the cooling system scraping the crud away from the cylinder walls. The cooling system doesn't flow well around 5-7 and 6-8 causing the back of the engine to overheat due to minimal coolant flow.
Steve
How did you determine 210-230 is to hot ? Check your ignition timing and points dwell.
What I assumed is that 210 is a decent operating temp. When I see coolant puking out it’s around the 230 mark or slightly past after I turn the car off. That’s the only indication I used to determine 230 was overheating.
.......I have a 1961 Olds 98, with the 394, 4bbl Rochester carb. I've had it for about 10 years or so, given to me by gramps. It has always run hot and/or overheated. I am wondering if these things just run hot or if I can pinpoint what the deep-rooted issue is. Here is all you need to know, I think:
I replaced the original rad years back, I accidentally hit the radiator with a tranny line running it back up to the front of the car because of a line swap I was doing. It leaked bad and never got it fixed. I simply bought a Champion aluminum one, in hopes it would help. It did not solve the issue.
It runs about 210 -230 and increases, especially on warmer days (here in MN it's about 90 degrees lately). If I hit the freeway, it will cool down to about 195. I can see the temp gauge drop. I installed a temp gauge btw. It won't puke out the overflow hose unless I fill the rad too high, which I have done. The coolant is about 1.5" below the neck of the radiator, cold.
I just flushed the system, lots of rust- colored water. Right now, it is 50/50 mix. Thermostat is a few months old, 180-degree. Rad cap is 15 lb. rated. Upper and lower hoses have the coils in them, no leaks there. Using the original 4 blade fan, but ordered a clutch, and will use a 6 -blade fan I have with the clutch, when it arrives this week.
Car has 97,000 original miles on it. I believe the carb is tuned great, it runs and drives great. Smooth.
Water pump has been replaced, no leaks from it.
Can anyone help me figure this out? What am I missing? Bigger rad? Do these 394's run hot? I feel like these engines ran properly years ago when they came out and that there is an issue I need to figure out. HELP! Thanks so much guys, I truly appreciate this. I feel like I am in good hands!
Originally Posted by eggydrummer
Not sure about the ignition timing. Never really dialed that in. I'll have to read the book and determine how to get it dialed in.
I will post some results and go over some of these suggestions. I do use non-ethanol Premium, always have.
Do you think the fan clutch and 6 blade fan would help as well?
-Heat riser valve functioning
-Get readings with IR thermometer on radiator
-Test accuracy of the temp gauge I installed
Originally Posted by eggydrummer
What I assumed is that 210 is a decent operating temp. When I see coolant puking out it’s around the 230 mark or slightly past after I turn the car off. That’s the only indication I used to determine 230 was overheating. is 230 safe?
Keep in mind, this is my opinion and others may have different thoughts.
You have overfilled the radiator and that has caused it to puke out coolant. A "headspace" in a cold radiator is correct. You do realize that liquids expand in volume when heated ? Don't overfill the radiator when its cold.
When these cars were new, they only had a "hot" light that was triggered by a sensor to come on when coolant reached a certain temp. Gauges can allow you to keep track of coolant temp. Obviously, the radiator will cool the coolant at highway speeds and you noticed that. I would say your radiator and cooling system is pretty good. Where the heat problem is, seems to be slow (stop & go) traffic.
A clutching fan, more fan blades and a shroud would help. Correct engine timing and points dwell could help, if it has gotten out of specs. Possibly bumping the ignition timing a couple more degrees advanced may help also. Have you checked tire pressure lately ? Low tires will make a difference.
Check the heat riser valve to see if its free to open.
230 is on the warm side, but sounds like that it is not a constant temperature. Slow speeds and slow engine speeds contribute to warmer coolant.
Newer cars have electric fans to turn on at certain coolant temps. I really don't think you need to go that far.
I have a 1966 Olds Toronado with 99,000 miles and I was out driving last week when it was in the 90's. Everything was just fine. I think you are thinking you have a problem, when really it isn't a problem. If you only had an "idiot light", would you be having a problem ?
You do no state if this is a new radiator cap. A malfunctioning radiator cap can/will cause the radiator to overheat & puke coolant - ESPECIALLY at idle. Very inexpensive ($9) & good safeguard to a properly functioning cooling system. It's very difficult to determine a malfunctioning radiator cap. If the car is at idle under normal operating temperature and it's overheating & puking coolant, chances are it's the radiator cap.
I did check the heat rise valve on the driver's side exhaust manifold; it was STUCK. Attached is a pic of the position I was able to move it (with a dead blow hammer handle, and a smaller hammer hitting the dead blow on the counterweight of the valve). Does anyone know if the position in the picture is open or closed? Whichever it is, it has moved to the postion pictured, and has been stuck opposite for god knows how many years.
Used a temp gun on the engine. I was getting readings of 230 from my temp gauge and it was damn close on the engine; radiator measured 218 degrees at the middle, that was the highest.
Upper rad hose read 220-221
Lower hose 209
Should there be different temps on the intake manifold? A jump of 254 degrees to 280 in an area. Is that common?
Looking at the heat riser valve. No coil there I took it off for now, part had broken off anyway
You do no state if this is a new radiator cap. A malfunctioning radiator cap can/will cause the radiator to overheat & puke coolant - ESPECIALLY at idle. Very inexpensive ($9) & good safeguard to a properly functioning cooling system. It's very difficult to determine a malfunctioning radiator cap. If the car is at idle under normal operating temperature and it's overheating & puking coolant, chances are it's the radiator cap.
Norm, it is only a few weeks old if that. It is a 15 lb cap.
I did check the heat rise valve on the driver's side exhaust manifold; it was STUCK. Attached is a pic of the position I was able to move it (with a dead blow hammer handle, and a smaller hammer hitting the dead blow on the counterweight of the valve). Does anyone know if the position in the picture is open or closed? Whichever it is, it has moved to the postion pictured, and has been stuck opposite for god knows how many years.
Used a temp gun on the engine. I was getting readings of 230 from my temp gauge and it was damn close on the engine; radiator measured 218 degrees at the middle, that was the highest.
Upper rad hose read 220-221
Lower hose 209
Should there be different temps on the intake manifold? A jump of 254 degrees to 280 in an area. Is that common?
Looking at the heat riser valve. No coil there I took it off for now, part had broken off anyway
That weight should be hanging straight down when the valve is wide open.
Try to move it some more.
If you can't move it anymore, then as suggested, remove the flap valve inside of it.
The heat riser isn't needed on a car that doesn't operate in freezing weather.
I did check the heat rise valve on the driver's side exhaust manifold; it was STUCK. Attached is a pic of the position I was able to move it (with a dead blow hammer handle, and a smaller hammer hitting the dead blow on the counterweight of the valve). Does anyone know if the position in the picture is open or closed? Whichever it is, it has moved to the postion pictured, and has been stuck opposite for god knows how many years.
Used a temp gun on the engine. I was getting readings of 230 from my temp gauge and it was damn close on the engine; radiator measured 218 degrees at the middle, that was the highest.
Upper rad hose read 220-221
Lower hose 209
Should there be different temps on the intake manifold? A jump of 254 degrees to 280 in an area. Is that common?
Looking at the heat riser valve. No coil there I took it off for now, part had broken off anyway
That weight should be hanging straight down when the valve is wide open.
Try to move it some more.
If you can't move it anymore, then as suggested, remove the flap valve inside of it.
The heat riser isn't needed on a car that doesn't operate in freezing weather.
The heat raiser valve operation is essential to proper engine operation. Oldsmobile factory engineers incorporated the heat raiser into its engines for several reasons. If it wasn't needed it wouldn't have been installed. It warms the intake manifold to prevent carburetor icing in cooler temps. It keeps the atomized fuel/air mixture in suspension to prevent puddling in the intake manifold. Improper operation or elimination of the heat raiser valve will (if stuck open or removed) cause poor engine operation when cold, and cause poor fuel economy. (If stuck closed) may cause fuel boil over, may contribute to higher engine temps.
You have found a defective part. Repair or replace it as needed. JMTC.
Still haven't zeroed in on the overheating issue, but can someone explain if ignition timing could be the culprit? How to adjust? Could I shift the distributor cap and see if that solves the issue?
Could my ignition timing be off? I have toyed with it a little by spinning the distributor a couple years back, but the thing runs very nicely. Idles nicely. Maybe I have the timing off? Which way would I rotate the cap? Could that solve the overheating issue??
Yes the timing could be off and be contributing to the problem. No rotating the cap won't work. The point gap should be set with a dwell meter and the timing with a timing light.
Unlike most American V8s, CCW = advance and CW = retard. I believe this applies to the first generation engines as well as the later ones.
If it's running retarded, that could contribute to an overheating condition. Generally speaking, you want to run as much advance as you can without inducing detonation (spark knock). You should check it with a timing light, but for now a quick and dirty method is to advance the static in small increments until you hear detonation and then back off from there.
Could my ignition timing be off? I have toyed with it a little by spinning the distributor a couple years back, but the thing runs very nicely. Idles nicely. Maybe I have the timing off? Which way would I rotate the cap? Could that solve the overheating issue??
You don't need the heat riser, many of us have cut stuck flappers out over the years with no adverse effects to engine operation. Yes, engine timing is critical to engine performance and operating temps.
You don't need the heat riser, many of us have cut stuck flappers out over the years with no adverse effects to engine operation. Yes, engine timing is critical to engine performance and operating temps.
His was jammed closed. So he has an issue that needs to be resolved. Either remove it, open it permanently or fix it.
Just took it out for a spin; it is about 90 degrees here in MN right now, and I wanted to test it out.
When at a very slow creep, like creeping around inside a car show with people walking around, it will climb to 230 after a lot of creeping (under 10 mph) or at a stoplight. The water temp rises. When I throw her in neutral, however, with the RPM's going up a bit, i can see the gauge slowly cooling down. If i give it a few quick high revs, it will move the needle even more.
Could my in-gear idle be too low?
Also, my Olds service manual for this vehicle says the original red 'dummie' lamp, or 'hot' lamp will come on at +- 243 degrees. I have never let the Olds get to that temp with this water temp gauge.
It is accurate; I used an IR gun to check different parts of the engine to compare to the gauge as well as the rad hoses, which are even slightly lower than that.
1) Could it just be a warm running 394?
2) Could my idle be adjusted to higher RPM's?
3) What do you make of the revving and the cooling down? I get it circulates more water around the engine.
4) Would a bigger rad help or maybe solve? This is not the original. The original was larger and as far as I know (I didn't have a water temp gauge years ago when the original rad was in it) This is a Champion aluminum one, smaller, with a 20 pound rad cap.
It’s not your idle speed. Flush the 70 years of crap from the cylinder block ( assuming the original engine) and put back at least the original sized radiator.
It’s not your idle speed. Flush the 70 years of crap from the cylinder block ( assuming the original engine) and put back at least the original sized radiator.
yes original engine. Sat in a garage from about 1991 to 2010
Funny you say that….I am going to post pics of residue and particles (attracted to my magnet) that present themselves in the top of the rad after driving and letting the car sit overnight.
small crumb, rocky, jagged looking, mixed with rustiness.
original rad is long gone was damaged and never repaired.
Out of curiosity, did you open the plugs on the block when you flushed/cleaned out the old coolant? After I bought my car, I flushed the system and I had some pretty awful junk come out of the block. Also did you double check to make sure no air in the system?
d1
what is the proper way to flush, when opening the plugs on the block? I need to do them same in my 61 olds 98. Could be the source of my overheating issues. Sat for 19 years and never drained the block plugs
Try a cooling system flush with the block drains open or even better pull the cylinder block core plugs and clean the 70 year old crap out. Then install the correct sized radiator that the engineers built into the car. Keep us apprised of your progress
Last edited by Dynoking; July 7th, 2022 at 02:27 AM.
Reason: Spelling grammar
Heat riser is open; stuck open, but not closed anymore. It was so hard to move. Had to hammer it with a wooden rod.
I have not hit the tune up yet. I need to get a timing light yet.
The heat riser is a plate mounted to a rod, that goes outside of the manifold. It is possible that you "opened" the outer arm, and the plate inside is still frozen closed. If you're still having problems, investigate this.
Eggy, I moved your post to a new thread and didn't realize you already had an open thread on your Olds overheating. Now your responses are all in this thread.
To answer your question I flushed the coolant out of the 455 in my 71 98 by simply opening the petcock on the bottom of the radiator and using a garden hose in line with the heater core. You can get kits at the auto parts store specifically for this.
I also removed the block drains on my 6.9l IDI in my 86 Ford F250 and flushed it with the same kit. Then I replaced the block drain plugs with petcocks.
Just make sure you refill with distilled water and coolant mix appropriate for the climate you live in (I run 50/50 in OK).
Last edited by Olds64; June 30th, 2022 at 10:35 AM.
Reason: Ooops!!!
The heat riser is a plate mounted to a rod, that goes outside of the manifold. It is possible that you "opened" the outer arm, and the plate inside is still frozen closed. If you're still having problems, investigate this.
I was able to move the counter weight in the position that someone here told me to move it so that the valve would be open. Maybe it’s just spun without actually moving the valve?
Here are the small particles
Here is a picture of the particles are found in the top of the radiator overnight after has been completely cooled I tracked them to a magnet it happens every time I drive it and let it sit overnight.
June 22nd, 2022, 06:00 PM
'61 Olds 98 overheating?
was damaged and never repaired.
Flushing coolant with open drains?
