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Author Topic: car runs hot only long 20 miles or longer  (Read 6191 times)

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bird man1969

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car runs hot only long 20 miles or longer
« on: June 10, 2007, 01:04:26 PM »
I recently purchased a 69 firebird 400 4 barrell with air car with new radiator, water pump, heater core.  I Changed the thermostat to 160, and changed the lifter rods and valves on passenger side due to a tap.  I Found the tips were worn out and 2 rods were bent.  I put in a tempuataure gauge and it runs at about 190, if I drive for a long time it goes to 230.

I don't know if the radiator is not big enough or if the water pump is not circulating fast enough.  It is getting very fustrating.  I would appreciate any advice you could give me to help remedy the problem.

ttopformula89

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Re: car runs hot only long 20 miles or longer
« Reply #1 on: February 09, 2008, 07:44:38 AM »
If you replaced all of that then Your fan "could" be the problem, if you want to keep the original look then you could try replaceing the fan clutch, I however found that I get better gas mileage, more power and better cooling when I switched my belt driven fans over to electric. Its not hard to do, it would only take an amature mechanic about $160 and 2-3 hours time. I just did this conversion myself 2 weeks ago and went from 10.6 MPG to 16.6 mpg and I can FEEL the power increase, not to mention it runs much smoother and quieter this way, and after experiancing the difference myself I plan on switching every belt driven fan that I own now, and in the future over to electric. For that size radiator I would suggest 2 - 14inch electric fans with an adjustable thermostat, which will allow you to adjust when (what temp) you want your fans to turn on. You can get them at most any auto parts store, or on ebay, but the e-bay fans seem to be to expencive for my taste. Not to mention the electric fans push/pull WAY more air through your radiator quieter and faster. Heck if you dont do it for the cooling boost you get do it for the mpg you will gain, I know I will save enough in fuel within 2 months to make those fans pay for themselves.

Hope this helped some.

Ken

Bill Simcox

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Re: car runs hot only long 20 miles or longer
« Reply #2 on: February 10, 2008, 07:56:17 PM »
Birdman:

Diagnosis of cooling sytem problems can be very frustrating and expensive, should you utilize a repair shop that like the part replacement method of troubleshooting.
Common cooling system problems are usually on of two type of problems. Coolant flow or air flow. There are of course others, including combustion gas heating of the coolant, caused a cracked cylinder head, blown head gasket, etc. The trick is to detemine which is at fault. From your description it kind of hard to decide. Driving only 10 miles could cause a heat up, depending on traffic and weather conditions.
Generally speaking a coolant flow problem results in oveheating over a relative short period and requires a lengthy cool down.
An air flow problem on the other hand usually appears just the opposite. Slow to overheat and will cool down quickly when the proper air flow is introduced.
A flow problem can be caused by numerous problems and while it is the most common to occur, is also the hardest to find.
Given the new parts you say are already installed it almost sounds like the previous owner was having a problem and was using the troubleshooting method I described at the beginning of this email.
It has been my experience that most individuals and a lot of repair shops for that matter, are not familair with the Pontiac engines. They either don't bother to check, or don't know enough to check, the clearance of the water deflector (tin plate mounted betwen the water pump and the block) to impellar clearance. A clearance in excess of .060" will result in at least partail flow loss and pump cavation. An overheating condition usually results. I have seen clearances on brand new pumps in the .130" - .150" range, so a new pump that hasn't been properly clearanced might not flow worth a darn.
An air flow problem can be as simple as external plugging of the radiator core, (dirt, leaves, bugs, etc.) Damage to the radiator cooling fins, improper fan, bad fan clutch, loose fan belt, or possibly one or more of the factory installed air dams are missing. I've seen a lot of first generation Firebirds with missing air dams. (The air dams are sheet metal or fiberglass, pieces that direct all the air coming through the grille across the radiator).
If you can provide a little better description of the symptoms we might be able to offer a more directed diagnosis.

Bill Simcox
NFTAC Tech Staff

MILKTRUCK

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Re: car runs hot only long 20 miles or longer
« Reply #3 on: February 12, 2008, 12:47:00 PM »
i have a similar problem with overheating on a 403, was wondering if mine could be caused by the impeller clearance. if it is, how to adjust it? press the shaft into the housing more to bring the impeller closer to the plate?

Bill Simcox

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Re: car runs hot only long 20 miles or longer
« Reply #4 on: February 12, 2008, 03:04:45 PM »
Actually leaving the impellar off the shaft further will decrease the clearance. But yes you are correct, placement of the impellar is the secret. If you furnish your email address I will attempt to locate and forward one of the articles I have stored on my computer that describes the procedure as well as where and how to measure.

Bill

National Firebird and Trans Am Club Message Board

Re: car runs hot only long 20 miles or longer
« Reply #4 on: February 12, 2008, 03:04:45 PM »


 

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