overheating

[Anonymous]

When I get stuck in traffic my car overheats. It started happening about a month ago after i had the engine rebuilt. When I looked under the hood I noticed that there was no fan shroud so I modified one to fot but is does not fit correctly. Is it that or should I have my radiator recored?

 

[Anonymous]

It's possible that the block was not cleaned properly and the loose particles
are plugging the radiator. I had that happen with the V8 that was originaly in my car. It plugged the radiator three consecutive times. The first time I paid to have it rodded. the second time I had it pressusre blasted. The third time I took out my soldering torch removed the top tank and rodded it with a heavy strand of wire and then soldered it back together with radiator solder (50% tin 50% lead) and I installed a ganno coolant filter cost $50 but worth it that thing saved me from having to rerod the radiator at least four times. Oh and if you do by one I recomend the brass one stronger longer, lasting,ect.

Now that I've said that, I recomend that you remove the radiator cap and bottom hose stick the water hose in the top with the water turned all the way on. If the radiator over flows instead of running out the bottom it's plugged and needs to be rodded. If it doesn't I would say time for a new water pump or it could be the thermostat.


Good Luck,
Chad

 

[mustang6]

Usually when a radiator is having internal flow restriction (plugged up) problems the overheating occurs at higher speeds where the engine is creating greater heat but the coolant can't flow faster to take advantage of the increased airflow through the radiator.

Overheating at lower speeds is usually an airflow/heat overload problem. Rebuilt engines create more heat and place more stress on the cooling system for a couple of reasons. One is just the increased friction of new parts with close tolerances, this will ease up as the engine breaks in over the first few thousand miles. The second is that a bored out engine transfers more of its heat through the cylinder walls and into the coolant. If you aren't flowing enough air over enough surface area to transfer enough heat out of the cooling system you will overheat, and a cooling system that was marginal with an old engine just might not cut it with a new one, especially at low speeds on hot days.

I've solved this problem in the past by trying things in the following order (stopping when the problem is solved):

1. Install a fan with more aggressive blades (preferably a flex fan so the increased air draw at low speed doesn't cost me high speed power loss).
2. Install a good fan shroud to draw air through the radiator across more of it's surface area.
3. Install an electric pusher fan to help push more air through the radiator when needed.
4. Install a thicker and/or larger radiator to get more cooling system capacity and surface area.

 

[CobraSix]

Check the simple stuff first.

1) Check your fluid level. I know this seems obvious, but remember, if you fill up the radiator after the cooling system is drained, you'll only get about 60% of the cooling fluid in there. You have to run it on the road for a short period (or at least get it up to operating temp), let it cool, and then top off again. If you don't have enough fluid, you'll overheat at low speeds.

2) Replace the thermostat. It's $5 and easy to do. Get either a 180* or a high flow 192*(or 195*, sometimes they have different ones). See if that does anything.

3) Flush your system. The flushing kits usually only run $15 from Autozone. You may have crud as mentioned above. If you see any major discoloration, then that may be the issue. Check your hoses and make sure they aren't collapsing.

4) If that's not the problem, look at your water pump. If it was pulled and left sitting during the rebuild process, it could be bad. If there was grit in there, it may be toast too.

5) after that, look at your radiator. Personally, I wouldn't mess with recoring. Just get a new 3-row radiator and be done with it.

Electric fans, shrouds, and the like are really just stop gaps for other cooling issues. Sure, electric fans can increase HP since they can cycle. Shrouds will help at low speeds. But honestly, if your stock cooling system (minus the old 2 row) is up to snuff, there should be no way your car overheats. I've left my car idling for 30 minutes in 98* weather and the car doesn't even reach 180* (that's my thermostat temp).

Slade

 

[65coupei6]

You might also try a new radiator cap. What PSI are you using now? 13? If your system is in good shape you can try a 16.

 

[gtm1086]

Install a 160 degree t-stat and a 14 to 16 psi cap.

 

[LaGrasta]

Just what CobraSix said...

 

[Anonymous]

I was gonna say we dont need a shroud....so its NOT t he problem

I say water pump

 

[Anonymous]

It has a new water pump.

 

[MercuryMarc]

My "cooling problems" turned out to be a stuck brake master cylinder check valve that would keep ther brakes engaged after several pumps on the pedal. I found this out after a MAJOR cooling upgrade (alum rad, tranny cooler, electric fan, 160 degree thermostat, electric temp sensor switch). But heck - now my car never gets close to overheating and I've saved a few HP with the electric fan (trying to be optimistic...).

Good Luck!
Marc in SF
63 Comet Ragtop
Dual Cupholders
http://mercurycomet.net

 

[Anonymous]

First off, when you say overheating in traffic, is it boiling over and puking coolant? Or is it an indicated high temp on your gauges?
Unless it is also puking coolant, you may just have a gauge problem. It is not uncommon to have an incorrect or faulty temperature sending unit on the engine that can make the gauge read incorrectly. An IR thermometer gun is a nice way to check temperatures and varify if the gauge is incorrect.

Don't overlook the ignition timing. Retarded timing will contribute to overheating problems. A malfunctioning vacuum advance cannister is a common cause of overheating at idle. Initial timing may be correct, but if the vacuum can is leaking, you may not be getting any advance at idle.
Along those lines, you might need to verify that the outer ring of the balancer has not slipped. Verify that the reference point that you are basing the timing on is correct. Meaning, make sure the engine is at TDC of the #1 cylinder when the timing marks on the balancer indicate it is at TDC.

These things don't cost you anything to check and may save you the expense of needlessly replacing cooling system components.

Finally, a 37 year old car may just need a new radiator.
Doug

 

[Anonymous]

Install a 160 degree t-stat and a 14 to 16 psi cap.

IMO if you do change it i'd get a high flow one... from mr gasket. the flow size is like comapring a quarter to a half dollar.

ditto on almost what every one else said

 

[Anonymous]

My rebuilt engine ran a little hot at first but did cool down as it broke in.

It was mentioned above, but I found that after my car overheated several times (with my old motor) my lower radiator hose was very soft and squishy even though it was recently replaced. I got the hose with the wire in it and there is no way that baby is going to close down on me!

 

[CobraSix]

I wouldn't use a 160* thermostat for the same reasons as the shroud and stuff...it would be compensating for another problem. With a new cooling system, 192* thermostat (stock temp) and the only upgrade being a 3 row radiator, I have absolutely no cooling issues at any outside temp or running speed. My only issue is that it doesn't get warm enough in the winter to pump out enough heat (new heater core).

A good point was brought up...get a mechanical gauge to check the temps. It could just be a faulty TSU. Do that...run it, and write the temps down.

Slade