Radiator / water pump issue?

swissboysupra

New Member
Jun 4, 2008
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Utah
Got a 1990 MKIII and engine started overheating. Did a radiator pressure test and they said it had a small leak. Wasn't sure if it was necessary to replace but I bought a new Mishimoto Radiator and installed it myself. Put coolant in and drove it around the block. Overheated quite quickly. Radiator is PIPING HOT!!! Sucks! Hoses look ok. Do I need to look into replacing the water pump? Or how do I go about testing the water pump?
 

hvyman

Dang Dude! No Way Man.
Staff member
Apr 17, 2007
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Fullerton,CA
take the belt off and see if it spins freely. might want to check your thermostat and rad cap as well.
 

swissboysupra

New Member
Jun 4, 2008
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Utah
hvyman;1339500 said:
take the belt off and see if it spins freely. might want to check your thermostat and rad cap as well.

Thanks. I will try that. Do I need to loosen anything for taking the belt off? It is quite tight...
 

swissboysupra

New Member
Jun 4, 2008
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Utah
rayall01;1339565 said:
Loosen the alternator adjuster, and mount bolt. That will allow you to remove the belt.

I see.. thanks. Sorry I am a novice and taking my first stab and fixing the car myself....
 

mkiii222

Member
Mar 31, 2005
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Troy, MI
We all started somewhere.

These might help:
TSRM: This site also has an EPC (electronic parts catalog)
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=CO&P=6

Champion Toyota: (good prices and kind to the Supra community)
http://www.trademotion.com/partlocator/index.cfm?siteid=213747

The pump is part # 16100-49805-83 ($82). There are some parts you can get away with an aftermarket, but why gamble on quality.

One thing the TSRM doesn't mention but I found easier when replacing my water pump: Remove the radiator. It gives you so much more room to work and prevents scraping your knuckles on the fins.
While it's out you can spray it out, inspect it, and replace the lower hose.
 

swissboysupra

New Member
Jun 4, 2008
15
0
0
Utah
mkiii222;1339611 said:
We all started somewhere.

These might help:
TSRM: This site also has an EPC (electronic parts catalog)
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=CO&P=6

Champion Toyota: (good prices and kind to the Supra community)
http://www.trademotion.com/partlocator/index.cfm?siteid=213747

The pump is part # 16100-49805-83 ($82). There are some parts you can get away with an aftermarket, but why gamble on quality.

One thing the TSRM doesn't mention but I found easier when replacing my water pump: Remove the radiator. It gives you so much more room to work and prevents scraping your knuckles on the fins.
While it's out you can spray it out, inspect it, and replace the lower hose.

Thanks. The TSRM link is very helpful! I figured it's easier to replace the water pump when the radiator is out... Dang. Now I got to drain and remove it for the 3rd time. Beginner's learning curve...
 

mkiii222

Member
Mar 31, 2005
697
0
16
Troy, MI
swissboysupra;1339648 said:
Thanks. The TSRM link is very helpful! I figured it's easier to replace the water pump when the radiator is out... Dang. Now I got to drain and remove it for the 3rd time. Beginner's learning curve...

Don't feel too bad. I replaced the hoses and did a drain/fill 2 weeks before I did the water pump. Mine had a pinhole leak in the bottom of the gasket that only showed up in the 'warm up'/'cool down' temp ranges, cold it didn't leak and fully warmed up it didn't leak.
 

swissboysupra

New Member
Jun 4, 2008
15
0
0
Utah
hvyman;1339500 said:
take the belt off and see if it spins freely. might want to check your thermostat and rad cap as well.

Thanks everyone for your help. After replacing the radiator ($200+) and almost replacing the water pump, it turns out it was a $12 thermostat....! But at least the new all aluminum radiator looks wicked...! :icon_razz