Looking for help...in all the wrong places

[Nlbloch]

I have a serious overheating problem and have nearly run out of ideas. Can anyone suggest other places to check?

I have checked and reset the timing.
Inflated the tires.
Checked radiator flow --it runs quickly out of the rad when lower hose is removed.
Checked hoses - all clear
Replaced head gasket. Torqued over several weeks to 60 lbs.
Used Bar's anti-leak
Drained and running on pure water
Run the car lean -- or rich. Makes no difference.

There appears to be a little foaming when the engine runs and the water is hot. I initially thought that might be some residual Bars in the system. The is just a little bubbling in the water.

Could it be the water pump? It is relatively new (five years)? How could I test to be sure? Fan appears to be turning properly and belt is right tension.

The car overheats after driving only about ten minutes. It overheats when driving fast or slow. When I say overheat, I mean the red mercury in the radiator cap/thermometer rises quickly to the top. I mean the radiator becomes a geyser and the admiration of all the July 4 parade watchers.

One thing I have not yet done is back flush the radiator. I didn't do that when the discharge flow seemed fast and the water was clean of debris.

Your suggestions greatly appreciated.

[Ross/Kzoo]

I would get an infrared heat gun to check the different areas of the engine and cooling system. Well worth cost for around the home uses also.

[Mitch//pa]

also ck for hydrocarbons in the cooling system

[TinCup]

Boy have I been here. Has anything changed? Has this radiator worked before? Is it a 2 core or a 3 core? It makes a difference. This is a simple cooling system. Radiator should be your first item to check especially with the symptoms your describing. As Ross said go buy yourself a cheap infrared heat gun and check the radiator at the top where it will be it's hottest and at the bottom where it will be it's coolest. If you have a blown head gasket you can get a test kit at NAPA to test it.

[700rpm]

Flush and back flush the cooling system. Do you have a 3-tube radiatior?

[Duffy1]

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Check and see if all the fins are attached to the tubes. It can still flow good and not cool correctly if the fins have come loose from the tubes . How old is the radiator? Do a search on radiators . Lots of info .

[satelite]

What is the history of the engine?. Did it always overheat?, Have you actually measured the temperature?, How is the car timed?, Are there bubbles in the water? (an indication of a blown head gasket). It is not uncommon to have a cracked valve seat at the center of the engine. This will cause the water to super heat. Just some things you might check.
Don in SC

[Tom Wesenberg]

I've always found the flow test to be worthless. As far as backflushing the radiator, I can see flakes of rust setting on top of some tubes and when water is forced backwards they tumble around, but don't wash out. I removed my radiator, layed it flat, filled it with water, and turned it upside down to remove many rust flakes. I did this 4 times before no more rust flakes came out. First I ran Cascade in the system for a couple days, just in case any old grease was in there, then I ran 2 1/12 gallong of pure white vinegar for 30 days to clean out the system.

If some of your tubes are plugged solid, the vinegar may not get them open, but for only $7 it's worth a try.

[Ken B]

Possible intake manifold leak?

[johnsor]

Seems that you have checked most of the common reasons for over heating, however no mention of the possibility of the water pump circulating too much water too fast. In re-reading the instructions that came with my new leak less water pump, they advise to cut or grind down the water pump vanes by about one third to reduce its flow capacity so the water will have a longer exposure to the cooling ability of the radiator. Makes sense.

[Bluebell]

Nlbloch, I'm not sure that others have taken note of your important clues.
You stated you have bubbles rising in the water. It can only be two things. the Water pump(s) are drawing air in (unlikely) or you have combustion gases getting into the cooling system. Any gas in the cooling system causes local overheating, the same as boiling would except at a lower temperature.
If you see combustion gas bubbles rising in the water at idle, then it will be a lot worse under load. little bubbles become big ones.
You either have a leaking head gasket, or a crack, or both.

It is important to do all the other stuff as well, when you fix it. For example, a scaled block, or a blocked radiator could have caused the problem in the first place

[Mike V. Florida]

Originally Posted by Nlbloch

I have a serious overheating problem and have nearly run out of ideas. Can anyone suggest other places to check?

I have checked and reset the timing. What method did you use?
Inflated the tires.
Checked radiator flow --it runs quickly out of the rad when lower hose is removed. If the radiator is not holding the correct about of water. a flow test means little.
Checked hoses - all clear
Replaced head gasket. Torqued over several weeks to 60 lbs.
Used Bar's anti-leak
Drained and running on pure water
Run the car lean -- or rich. Makes no difference.

There appears to be a little foaming when the engine runs and the water is hot. I initially thought that might be some residual Bars in the system. The is just a little bubbling in the water.

Could it be the water pump? It is relatively new (five years)? How could I test to be sure? Fan appears to be turning properly and belt is right tension. The car can run without the water pimp so any motion would not be the cause IMO.

The car overheats after driving only about ten minutes. It overheats when driving fast or slow. When I say overheat, I mean the red mercury in the radiator cap/thermometer rises quickly to the top. I mean the radiator becomes a geyser and the admiration of all the July 4 parade watchers.

One thing I have not yet done is back flush the radiator. I didn't do that when the discharge flow seemed fast and the water was clean of debris.

Your suggestions greatly appreciated.

Has it always done this? What work was done just before this started?
So my thoughts are, the timing (I know you checked and re checked it but it has happened to others), the radiator is clogged, the brakes are dragging.

I know you want answers and I'm asking more questions. The bottom line is that many things can cause your problem and there are many things to try. We are just trying to narrow down the cause to make the fix as simple and inexpensive as possible.

[Ron Lachniet]

I had a similar problem last week. On a long hill I would spew water and my engine would start missing. I put in a new coil,condenser,points,head gasket, and went through all my wiring. None of this made any difference. out of desperation I removed the radiator and brought it in. They found a crack in the neck and a leak under the hood rod bracket and lots of hidden crud inside. I put the radiator back in last night and did a test run. I ran the same long hill and it ran just fine. Something to think about.

[eagle]

Make sure you are running with the spark lever advanced as far as possible without ping. Even a couple clicks too retarded will cause overheating although a geyser at idle in a parade is REALLY overheating! Cavitation of the water pump could also be a problem except there again, at low rpms as in a parade it should not be the cause. I would check for gasses in the radiator and make sure the radiator is clean clean clean.