# Overheating: Radiator and Lower Hose cold, top hot.



## ejg3855 (Sep 23, 2004)

Problem with the car is overheating.

Symptoms: 

Lower Radiator Hose is cold.
Radiator is cold.
Upper rad hose is hot and seems like there is alot of pressure.


Diag:

Pulled T-stat out and drove car, still over heats. Rad is still cold, upper hoses still stupid hot.

I am thinking the rad is blocked or there is a large air bubble in it. Its odd this happened on the coldest day of the year though.

Water pump is working pulled CTS and it pumps fluid out.

Help!


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## Cryser (Sep 9, 2009)

take off the coolant ball cap, turn the heater to max and let the car heat all that will burp your system. Taking the thermostat out and driving really doesn't prove anything, you can over heat without a thermostat in simply because of the fact that coolant in flowing so much faster that it has no chance to really pick up heat and remove it from the block, take out your thermostat and test it in boiling water... if you need the test spec check bently or shoot up here and I can find them for you when I go back to class on tuesday. Word of warning when replacing the thermostat make sure the metal tangs are vertical or it will leak like crazy.


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## awpturbo (Jan 9, 2009)

I hate to say this its the water pump...... these suck to replace if you have never done it. they run of the timing belt........ second how many miles are on the car?

I had the exact same issue right after I bought mine a few years ago.


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## Twopnt016v (Jul 5, 2009)

You need a water pump. When you pulled the Tstat you should have reached in the hole with your finger and felt the water pump impeller. I bet it has a plastic impeller and it is slipping on the shaft. If this didn't start after a repair on the cooling system then you can most likely rule out air in the system. If you removed the tstat and its still overheating then its 99.5% chance you need a waterpump. The only other thing could be a clogged radiator but that isn't as likely as the waterpump. When you replace the WP you should go ahead and replace the timing belt and tensioners...:thumbup:

edit: you can pull the upper and lower radiator hoses and run water thru the radiator with a water hose and make sure that is free flowing. The best way to check the water pump is pull the return hose off the expansion tank and see if water flowing. Keep in mind when the WP slips on the shaft it will work fine and appear to be pumping good at idle when you check but when you drive the car the impeller starts slipping on the shaft and you over heat...


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## ejg3855 (Sep 23, 2004)

yea I am at the water pump conclusion as well. I have done a handful of 1.8T timing belts its no issue.

I did stick my fingers in the t-stat hole and it felt plastic. its not original unless I got dicked by the guy that did it. 

it does pump coolant but I can't tell how well. 

its going to the shop its too cold to do it. 4F here last night.

Sent from a phone.


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## awpturbo (Jan 9, 2009)

and not to self... I would only go with one from a dealship or one that is OEM. I know you are thinking why would I put another plastic impeller one back in when I can put a metel one in..... but I have had bad problems with the freeze plugs leaking on the ones that are not OEM... I dont know why but. I had had this OEM water pump for 2 years "knock Knock" and the freeze plug has not leaked.


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## ejg3855 (Sep 23, 2004)

awpturbo said:


> and not to self... I would only go with one from a dealship or one that is OEM. I know you are thinking why would I put another plastic impeller one back in when I can put a metel one in..... but I have had bad problems with the freeze plugs leaking on the ones that are not OEM... I dont know why but. I had had this OEM water pump for 2 years "knock Knock" and the freeze plug has not leaked.


yea I hear ya. I have put in at least 6 metals and never had a problem. there was a revision to the plastic ones that fixed the cracking issue. I just order my parts from GAP never had any issue.

I just dont have the time or space or heat to do this one.

Sent from a phone.


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## simonwa (Oct 15, 2010)

Cryser said:


> ...Word of warning when replacing the thermostat make sure the metal tangs are vertical or it will leak like crazy.


Thread revive:

IS THIS TRUE?!

just did my t-stat and the metal arms on the outside face are horizontal... Do I actually have to go in there and turn it 90 degrees??


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