Water pump or thermostat?

**mattgw86** · 01-26-2016, 09:14 AM

One of these two parts has recently failed on my car. A couple weeks ago, as I was leaving a restaurant, I noticed a big puddle of liquid under my car. I smelled it and confirmed it was coolant. I wasn't able to figure out where it came from, but the level in my car was a little low. I didn't have time to mess with it, so it got parked. The coolant temperature was a little higher than normal, but not high enough to be concerned.

Yesterday I decided to do done troubleshooting on my supposed coolant leak. I noticed the temp gauge on the dash was rising unusually fast and the fans weren't coming on, so I turned the car off and plugged in my laptop. The engine temperature was around 150. After a couple cycles of running and stopping the car (I didn't let the gauge get much more than 3/4) the temperature became high enough for the fans to come on. I also tried manually running the fans, but the temperatures rose the same add without the fans. I also turned the heater on full blast, but only got cold air and the radiator was still cold too.

I forgot to add, all this was after I refilled the cooling system to the proper level. I could see the radiator never getting warm with a stuck thermostat, but what about the heater core? Is that a sign that the pump is dead? I might just replace both anyway since the pump is 21 years old with 150k...

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***SSlowBoat*** · 01-26-2016, 10:40 AM

Originally Posted by mattgw86

One of these two parts has recently failed on my car. A couple weeks ago, as I was leaving a restaurant, I noticed a big puddle of liquid under my car. I smelled it and confirmed it was coolant. I wasn't able to figure out where it came from, but the level in my car was a little low. I didn't have time to mess with it, so it got parked. The coolant temperature was a little higher than normal, but not high enough to be concerned.

Yesterday I decided to do done troubleshooting on my supposed coolant leak. I noticed the temp gauge on the dash was rising unusually fast and the fans weren't coming on, so I turned the car off and plugged in my laptop. The engine temperature was around 150. After a couple cycles of running and stopping the car (I didn't let the gauge get much more than 3/4) the temperature became high enough for the fans to come on. I also tried manually running the fans, but the temperatures rose the same add without the fans. I also turned the heater on full blast, but only got cold air and the radiator was still cold too.

I forgot to add, all this was after I refilled the cooling system to the proper level. I could see the radiator never getting warm with a stuck thermostat, but what about the heater core? Is that a sign that the pump is dead? I might just replace both anyway since the pump is 21 years old with 150k...

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even with a stuck open stat you should get some heat. the main place air usually gets trapped on the cooling system is the heater core, and if you open the upper bleeder with the car running its on the suction side of pump, so if there isnt enough coolant in the line it will actually suck air into the system instead of bleeding it out.the stat takes 5 mins and maybe a half gallon of coolant to remove and check, if you have coolant on the bottom of the water pump BEFORE checking the stat, then id say your water pump is shot, especially since you had a puddle at one time. basically, replace both

**myltwon** · 01-26-2016, 10:54 AM

Proper bleeding required with lt1s, could be the issue

**mattgw86** · 01-26-2016, 02:01 PM

I think I'll replace both and take the opportunity to replace the leaky timing cover.

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***popo8*** · 01-27-2016, 09:31 AM

LTXtech.com IS my drug...
OWNER/ADMIN

**Injuneer** · 01-27-2016, 10:21 AM

Need to pressure test the system to figure out what dumped the "big puddle" of coolant on the ground. Check the reservoir. If it's overfilled, could be a problem with the overflow hose/pipe having a crack in it, preventing the system from pulling coolant back into the radiator as the cooling system cools down.

**mattgw86** · 01-27-2016, 11:58 AM

Originally Posted by Injuneer

Need to pressure test the system to figure out what dumped the "big puddle" of coolant on the ground. Check the reservoir. If it's overfilled, could be a problem with the overflow hose/pipe having a crack in it, preventing the system from pulling coolant back into the radiator as the cooling system cools down.

That's part of my concern, I couldn't figure out where it came from. I saw the puddle at the restaurant, drove home, and couldn't find where it came from. It never did leak again, even though I ran it a couple times. The reservoir was just a little below the "full cold" mark.

What I'm probably going to do is tear down everything in the front to take care of the oil leaks, then I'll go through the cooling system very thoroughly and flush it and the A/C system. Now is the best time since I have to redo my A/C system again due to an improperly ran line that wore through. That and it's not 300° outside yet...

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**bustedassz28** · 01-27-2016, 08:40 PM

If you decide to change the pump n stat, I've got one listed in the for sale section, less than 200 miles and a hyper tech 160 stat, save yourself some $$$$$