New radiator Overheating?

I changed out a radiator on my 97. I never had a problem with overheating. Was pretty consistent at 200 degrees. Now it likes to creep up into the 215 range. Do I need to burp the system? Any special technique to this.

No need to burp an open system. Just keep the overflow at least half bottle full. The air will push out when hot and draw coolant back in as it cools. Once you think you have it full, don't keep removing the radiator cap.

Aside from this theoretical method, some people have reported needing to squeeze the upper radiator hose a few times to make it all work right. Sounds weird, but maybe that forces more air out.

Hopefully you've installed the dealer-supplied factory T-stat, the one with the check-valve ball in it. Installed at 12 o'clock, it helps keep the system burped, as the upper hose and T-stat housing are actually the highest point in the system, not the ideal. You'll find threads, if you look, where folks swear by them, and others that say it doesn't matter. I use them, and knock on wood, have never had a problem with any of our fleet of four. There's my vote!

rockhead said:

I changed out a radiator on my 97. I never had a problem with overheating. Was pretty consistent at 200 degrees. Now it likes to creep up into the 215 range. Do I need to burp the system? Any special technique to this.

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Are you sure your radiator was bad. 210 is normal 215 not too bad. What T-stat do you have? Did you replace the hoses with the radiator? What mix of coolant are you using? Is you radiator Cap Good? Are your fans working correctly?

The old radiator started leaking a little. Never had an overheating problem. With the new one it does run hotter by 10 degrees or so. I did not change anything else in the cooling system. I will see if I have a little air in the system.

What radiator did you buy?

winterbeater said:

........The air will push out when hot and draw coolant back in as it cools. Once you think you have it full, don't keep removing the radiator cap...........

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Air, as well as hot coolant, will flow out of the rad and into the overflow bottle ONLY IF the outermost valve in the rad cap is functioning correctly. If the inner most valve in the rad cap malfunctions, coolant in the bottle will not flow back to the rad (as it cools) thus causing a low coolant situation in the rad. The coolant level in the bottle may still look fine but the rad could be low.

It's always best, WHEN THE ENGINE IS COLD, to remove the rad cap to check coolant level. If coolant is not visible in the neck of the rad (COLD ENGINE) then air is in the system and coolant is low thus reducing cooling efficiency.

RCP Phx said:

What radiator did you buy?

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yes, did you replace a two-core with a single-core?

As posted already, your open-system is self-burping, but you can accelerate the process. Engine cold, park nose-up on a steep incline so that the radiator cap becomes the highest point of the cooling system. Check the recovery bottle and make sure it is filled to the "cold" mark. Run the engine up to full operating temperature. Shut down and let it cool. Observe the recovery bottle and make sure that it maintains the correct coolant level. As the system cools a vacuum is created and will pull the coolant from the recovery bottle back into the system, just make sure it doesn't go and allow the system to pull air.

The radiator was just a cheapo oem style radiator. Since I first posted this I overheated pretty bad driving up a mountain pass. Was holding steady at about 215 - 220 then my gauge light flashed and it shot up to 260. I pulled over and it cooled down almost instantly and drove the rest of the way up at about 215-220 again. I then replaced the cap and tonight I am going to replace the thermostat with a stant hd with self drilled hole. I am starting to think I should just order a 3 row radiator to replace the ebay one I put in. But first I will try the thermostat then a water pump. I want all the stuff new under there anyway.

Replace the radiator cap. Make sure it is a 16# rating. Bad radiator caps cause more overheating than anything else. The cap should be replaced every 2 years.

i replaced my 3 core CSF radiator with a single core el cheapo from pepboys. I noticed no change in temps, aside from the new SINGLE core rad cooled down much faster when i got moving compared to the 3 core. I have driven very hard, and then been in bumper to bumper traffic blah blah blah no over heating issues at all. Been through conditions that if it was going to over heat, it would have...but it didn't.

I wouldn't blame the radiator i would look at other things. Perhaps temp sensor, rad cap, fan clutch ect ect ect

rockhead said:

The radiator was just a cheapo oem style radiator. Since I first posted this I overheated pretty bad driving up a mountain pass. Was holding steady at about 215 - 220 then my gauge light flashed and it shot up to 260. I pulled over and it cooled down almost instantly and drove the rest of the way up at about 215-220 again. I then replaced the cap and tonight I am going to replace the thermostat with a stant hd with self drilled hole. I am starting to think I should just order a 3 row radiator to replace the ebay one I put in. But first I will try the thermostat then a water pump. I want all the stuff new under there anyway.

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Change your coolant mix (a**uming 50/50 ethylene glycol/distilled water) to 30 ethylene glycol and 70 distilled water.

As mentioned by Old Man make sure the cap is good--without pressure it will boil over quicker.

Just for peace of mind test the coolant for the presence of combustion gasses--rent the tester and purchase the chemicals.

rockhead said:

The radiator was just a cheapo oem style radiator. Since I first posted this I overheated pretty bad driving up a mountain pass. Was holding steady at about 215 - 220 then my gauge light flashed and it shot up to 260. I pulled over and it cooled down almost instantly and drove the rest of the way up at about 215-220 again. I then replaced the cap and tonight I am going to replace the thermostat with a stant hd with self drilled hole. I am starting to think I should just order a 3 row radiator to replace the ebay one I put in. But first I will try the thermostat then a water pump. I want all the stuff new under there anyway.

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I'm with the others in regard to radiator.

Single row will cool quickly when the driving load is reduced ... but has difficulty providing sufficient cooling underload - in certain conditions ....

Once the engine temp exceeds the ability of the little radiator to cool ... its all over ... and confirmed by the temp spike - similar to what happens, when the radiator cap is faulty.

Your post comments above are just like reading the basic overheating causes in the FSM.

Hills, high weather temps, high speeds ......

30/70 or less antifreeze mix and a 180/185/190 thermostat might keep you out of trouble for a bit ... Its what I used for a long time ... but a better radiator is the fix ...

Be cautious of 3row radiators ... as they can have airflow issues ... Ive found a quality 2row is more than adequate ... altho most seem content with the CSF 3row performance.

Not all radiators are built the same ... internal flow tubes diameters vary as does fin style and spacing. The tubes in a good radiator can even be "dimpled" to tumble the liquid for improved heat shedding.

Aluminium ones are high maintenance but have a good service life if well built ... whereas copper / brass ones cool slightly better and are easier to fix in the event of a leak.

Is this a decent choice and price.
http://www.drivewire.com/basket.php?add_item_id=95846

Is this a decent choice and price.
http://www.drivewire.com/basket.php?add_item_id=95846
:skull1:

There's an echo in here.

You can say that again.

For anyone searching. It appears there was air in the system. Got it out and all is good.

old_man said:

Replace the radiator cap. Make sure it is a 16# rating. Bad radiator caps cause more overheating than anything else. The cap should be replaced every 2 years.

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I've always used a 13 pound cap in my '94 which is what the recommended psi is for my 4.0. Am I missing something?

Use of a 16 psi cap will raise the boiling point of your coolant without causing any problems--no cost cooling system upgrade.