67 GS 400 is running way hot

S

Shakadula

Member
Temp is around 210 degrees and goes up to 250 at a stop light. The thermostat is a 190. I think I need to go back to a 180. The car used to run at 200-205 but my gauge might be a little off.

New hoses and running the heat isn't helping.

Thoughts on checking the guage and the thermostat? 50/50 coolent and water
 
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180 I guess is the best bet.

I replaced my timing cover gasket and replaced the thermostat at the same time. Don't know why I got the 190.

Thanks.
 
67 buick getting hot

If you have a clutch fan it could be bad. Run it till it gets hot and watch the fan while somebody shuts it off. If it keeps spinning a bit after you shut it off, the clutch os bad. It will slip and not turn fast enough when the engine is running. if that's the problem, replace it with a thermostatic clutch not a viscous clutch as the thermostatic works better. As for the thermostat, once you hit 190 it should be open and flowing. The different temps are just a way to select operating temp. You really shouldnt need the 190 in it though. That was usually used on a smog motor as they run them hotter to burn all the fuel. Put in a 180 and leave the rad cap off while it warms up to make sure it is opening. Hope I helped you a little.
 
The 190 opening temp of the thermostat will not cause the overheating problem you describe. One that does not open properly might. There is absolutely no problems that should arise from running a 190 degree thermostat. You have other heating problems.
 
It was the thermo!

It was the thermo and a bit of a kink in the top hose when it got hot. Fixed and I'm a bit under 210 degrees.

Now for a new problem. I'm never going to get this car on the road at this rate!

Since 2001, I have had 2 rear main seals put in this car. The first one the engine was pulled and the second time in 2008, they did it with the engine in the car. I suppose they dropped the drive shaft and raised the motor because after having it back for 2 weeks, the ubolts shook the rearend diff so bad it killed the rear end. Just my opinion. Anyway, my question is why do I need to replace the rear seals so often. Is my crank bent? Both times they used rope seals. I think I am going to go to the rubber seals next time.

The first shop that pulled the motor were really good and told me they thought my crank might be bent. I don't know how they can tell without pulling the crank out. The second shop was just a bunch of jerks. Put a new carb on for me and now I can't use my Star Wars Air Cleaner. And they said they were car guys.

Thoughts on the crank?
 
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Seal surface may be worn but I seriously doubt the crank is bent if this is a running driving car. Other problems would make themselves known real fast. The main problem that I see is that the rope seals that are sold today in gasket sets are not the same as the ones from when the cars new. This nylon crap they are selling today just doesn't work worth a damn. Try the neoprene replacement. You should be able to replace this without pulling the engine.
 
If the sealing surface is damaged, it must be cleaned up, especially if you are going to move away from the rope. I think I would go back to a 180 thermostat too. The 195 is more for newer emissions engines.
 
What I thought...........

Thanks. That's what I thought. How about pulling the motor as opposed to raising it a bit in the car!:confused:


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Shakadula said:
It was the thermo and a bit of a kink in the top hose when it got hot. Fixed and I'm a bit under 210 degrees.
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No, you didn't fix it. 210 is still too hot for cruise and idle.

210 isn't hot enough to damage the engine, but at cruise and idle you should be very close to the thermostat rating. Work the engine harder, and the temp might climb a bit.

Shakadula said:
How about pulling the motor as opposed to raising it a bit in the car!:confused:​
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I think it's less work--and better procedure--to PULL THE ENGINE instead of dicking around with the engine in the chassis.

Just because it "can" be done with the engine jacked-up in the frame does not mean it SHOULD be done with the engine in the frame.

Takes about the same amount of time either way; and with the engine out, you can flip it over on an engine stand and work comfortably instead of half-assing the job by working on your back like a prostitute; or overhead on a lift.​
 
Finally got the motor pulled

I did pull the motor. Actually, not too bad but with just me, it is taking time. Finally got the gasket set and intake manifold gasket. I was surprised that the intake gasket is metal.

Anyway, I did a compression test (before I pulled the motor) and all is good and within spec so I am not going to pull the cyl or crank. I do want to clean out the oil and water passages and am looking for suggestions. I have a 150 PSI air compressor but am unsure of what to do at this point. Need help here.

Also, the heads. They seem pretty clean but since I have them off the motor, are there any suggestions on what I should do with them since I have them off the motor?

Last thing, I will be changing the color of the motor from Chevy orange to Buick RED.

Thanks in advance.
 
temps......

2 things will make a engine run hot most of the time.... poor circulation of coolant , or poor circulation of air thru the rad.... or both,,,, :D and ,,,, sometimes real late ign timing can do it.... make sure that the rad. is clean and free flowing,, and there is plenty of air coming thru it.... if you dont have a fan shroud , buy, build , or steal one and put it on.... or make sure the fan blade is within 1 in. of the rad. and multiple blades not just 4 ,,, at least 6 or 7..... and personally , I dont like clutches because they go bad and toss the fan thru the radiator... but they can cause over heating if they dont work right....I prefer to run either straight drive fan or electric fans.... set up right electrics have some advantages in city traffic.... to me,,, one would want a engine to have as much ''cushion'' temp. wise as possible,,,, not lower than 160 deg. but not very much over 200 either...Buick engines in the 50's thru 70's were designed to operate in that range.... nailheads, sbb's and bbb's.... so I go with ''old school '' ways and change thermostats in spring and fall...the way we used to do it.... 160 deg. in spring and 180 deg. in fall.... so the engine has a temp. ''cushion'' before it reaches the upper limits... if it wants to run cooler , it can......just some ideas
 
Rear seal Radom thoughts

Something out of balance: like a torque converter, (I've had that) mis aligned or bent flex plate(I've had that) mis aligned bell housing ,hard to screw up but possibe. Ford had trouble on the Aerostar with factory machining alignment and replaced abunch of transmissions and some engine bearings.
 
Thermostat

Go back to basics, the thermostat olny controls miminum operating temperature the maximun temperature is controlled by cooling water flow, radiator capacity, timeing(a retarted engine will run hot)and load on the engine
 
To cover all the bases....

Double check the coolant that was put in the engine.... Dex-Cool and ethylene glycol antifreeze can NOT be mixed. Put in the same system they will form a sort of mud and clog the system... Most people don't know and just grab a jug of Dex Cool at the parts store by mistake...
 
Without completely disassembling the engine and hot tanking it there is really not much you can do to clean any of the oiling passages. You can remove the oil pan and clean it and the oil pickup but that's about it. You should have flushed the cooling system before you removed the heads. Now if you try to flush the block you are going to get water down into the rest of the engine where it does not need to be. With the block completely drained I would get a good light and look down into the water jackets through the holes in the deck and take a look. Is there a lot of sediment or other goop down in there? If there is you might try to get it flushed out. If there is not then don't worry about it. If your freeze plugs are original I would inspect them closely and change any that are corroded. It will never be easier to change them than when the motor is out and on the stand. You might pull the block drain plugs and clean out behind them also. You are kind of in a hard position. You have not pulled the engine down far enough to do any meaningful cleaning. If the water jackets don't look too bad I would put it back together and try to flush it while it's running. In all my years in the automotive business I have never seen a heating problem that I would blame on sediment in the block. It would have to be full almost to the deck to cause a problem. As far as your heads go you can take them to a machine shop to have them checked out or just clean the sealing surfaces up and bag them in plastic bags to keep them clean till your ready to re assemble. On further thought there is one oil passage that it might pay to investigate and clean. That is the one that brings oil to the rocker shafts. You will not be able to just run a bunch of pressurized air through it. Find it, the oil feed hole, on the deck of the block and run a wire down through it and see if it has a bunch of crap down in it. A small passage brush and some carb spray will help. Hopefully there is just an open hole with some oil in it but if there is a lot of sludge it pays to try to get it out. All of this assumes you are using the original block. After 1970 they started oiling the top end through the push rods and quit using this oil feed passage in the block. Clean the corresponding passage in the heads also. You can use compressed air on the passage in the heads as it's open on both ends, if the rocker shaft is off.
 
Cleaning oil passages? Sea-Foam, Sea-Foam, and Sea-Foam :) It's always worked well for me... however, on larger engines you may want to leave it in for awhile... 30-40 minutes....
 
Found theoverheating issue

Seems the upper rad hose from NAPA was collapsing underheat. Put on a universal hose and the motor runs around 200 degrees in hot weather. Maybe 210 at idle. Anyway, motor is back in the car and running great. Now where is the warm weather

thanks everyone.
 
Last followup.......

Car seems to be running well after all of that work and about 2000 miles. My sunpro gauge measuring the water temp was out of wack. I put in a new water temp gauge and that reads 190 degrees even at idle. i
I appreciate the thoughts on the rear main seal issue as I never thought sbout the torque converter. I will look into that.

Thanks everyone. Can't maintain this car without you. :thumbsup:
 
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