Overheating question
Thread Starter
Drifting
Joined: Sep 2007
Posts: 1,442
Likes: 1
Overheating question
I noticed my car getting to 255 degrees right when I got home last night. I thought it was the thermostat and replaced it this morning. I found out that this wasn't the problem after refilling with fluid and trying to work all the air bubbles out. I took the radiator shroud off and saw that is had some grass and stuff in the fins so this could be some of the problem. Both upper and lower radiator hoses are hot and the drivers side of the radiator is pretty warm but the passenger side of the radiator is not warm at all and this is after that car hits about 250 degrees.
When I take the radiator cap off I can see the water boil right at the T where the water goes to the over flow tank.
Could this be a water pump going bad, air bubbles in the system or could I have gotten another bad thermostat. Is there a way to check my old thermostat to see if it is bad.
Thanks
When I take the radiator cap off I can see the water boil right at the T where the water goes to the over flow tank.
Could this be a water pump going bad, air bubbles in the system or could I have gotten another bad thermostat. Is there a way to check my old thermostat to see if it is bad.
Thanks
Safety Car
Joined: Aug 2000
Posts: 4,933
Likes: 30
From: San Rafael CA
Take the old thermo and put it in a pan of water. Put on stove with a thermometer that can read to 200 degrees or more (if you want to be accurate about it) - most meat thermometers will work. Heat the water and watch at what temp the thermo starts to open. Stock it should start to open between 190 and 200 degrees.
Don't let your SO catch you boiling engine parts in the kitchen ... most seem to take a pretty dim view of this activity ....
From your description of the radiator being hot one side and cold the other ... I'd vote for the water pump. The thermo is supposed to fail OPEN, so if it is bad you should see too LOW a temp ... not too HIGH.
Don't let your SO catch you boiling engine parts in the kitchen ... most seem to take a pretty dim view of this activity ....
From your description of the radiator being hot one side and cold the other ... I'd vote for the water pump. The thermo is supposed to fail OPEN, so if it is bad you should see too LOW a temp ... not too HIGH.
Safety Car
Joined: Aug 2000
Posts: 4,933
Likes: 30
From: San Rafael CA
I'd put my money on the water pump. You said earlier "Both upper and lower radiator hoses are hot and the drivers side of the radiator is pretty warm but the passenger side of the radiator is not warm at all and this is after that car hits about 250 degrees. "
If the radiator was blocked by leaves and grass you'd expect to find the entire radiator hot (as air is not flowing through it). So to me you have a coolant circulation problem. If it is running that hot (250) with two different thermostats (and now you know the old one was OK ... opening near boil is close enough that certainly the engine should be getting no hotter than about 200 to 210) ... I have to go with the water pump failing .... I'm assuming you've checked the serpentine belt is working OK and turning the water pump .... so it is most likely internal to the pump.
If the radiator was blocked by leaves and grass you'd expect to find the entire radiator hot (as air is not flowing through it). So to me you have a coolant circulation problem. If it is running that hot (250) with two different thermostats (and now you know the old one was OK ... opening near boil is close enough that certainly the engine should be getting no hotter than about 200 to 210) ... I have to go with the water pump failing .... I'm assuming you've checked the serpentine belt is working OK and turning the water pump .... so it is most likely internal to the pump.
Thread Starter
Drifting
Joined: Sep 2007
Posts: 1,442
Likes: 1
Just went out to check to see if the belt was spinning the pump and this time the car got to 235 and then cooled itself to 219!!! It would make sense that there were just air bubbles in the system and replacing a bad thermostat solved the problem. But the supposedly bad theremostat opened up when I boiled it. Im confused 
Team Owner
Joined: May 2006
Posts: 21,473
Likes: 356
From: Palmdale, Ca----- 2009 Cyber Gray 4LT A6 F55 452 RWHP 422 RWTQ- RIP 1998 C5 734 RWHP & 585 RWTQ-----
Check your fans and make sure that the HIGH speed fan is operating when it gets up to its turn on temp!
There has been a problem before where the High Speed sid eof the two fans go out or start to go bad and it will need to be replaced and you can get one at ECKLERS they stock them!
This will for sure get your temps high if the High Speed fan does not come on or runs slow!
Thanks,Matt
There has been a problem before where the High Speed sid eof the two fans go out or start to go bad and it will need to be replaced and you can get one at ECKLERS they stock them!
This will for sure get your temps high if the High Speed fan does not come on or runs slow!
Thanks,Matt
Thread Starter
Drifting
Joined: Sep 2007
Posts: 1,442
Likes: 1
Both of the fans are working properly. I thought I could drive it to the store but the temperature got to about 240 then down to 225 and then back up to 244 where it hovered for a while and then up to 258 (where i pulled over and let it cool).
When I got home I started the car and would let it idle and then rev to around 3k in 30 second intervals like one of the other posts said to do. It is slowly getting better but the bubbles seem to never stop. It will idle with no bubbles for a minute and then when you rev, the bubbles are steady for a good 10-20 seconds. I look at the bubbles in the clear T fitting beneath the over flow tank.
Earlier I was slowly taking the cap off and I could hear the water boil when doing so. Could the boiling cause more air pockets in the cooling system? Has anyone else taken notice that it takes a while to get all of the air out?
Thanks
When I got home I started the car and would let it idle and then rev to around 3k in 30 second intervals like one of the other posts said to do. It is slowly getting better but the bubbles seem to never stop. It will idle with no bubbles for a minute and then when you rev, the bubbles are steady for a good 10-20 seconds. I look at the bubbles in the clear T fitting beneath the over flow tank.
Earlier I was slowly taking the cap off and I could hear the water boil when doing so. Could the boiling cause more air pockets in the cooling system? Has anyone else taken notice that it takes a while to get all of the air out?
Thanks
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Safety Car
Joined: Aug 2000
Posts: 4,933
Likes: 30
From: San Rafael CA
If the coolant temp is about 212 or higher, and you remove the pressure cap, then yes, the boiling of the fluid will put bubbles all through the system. The temps you are reporting are just too high for a cooling system that is "normal". I still go for a bad water pump.
Tech Contributor
Joined: Jan 2007
Posts: 19,533
Likes: 1,196
From: Dyer, IN
If the thermostat is working, and one side of the radiator is cool, then you are not getting circulation=waterpump. There always exists a remote possiblity of radiator blockage;however, probably not the case if the systems has been maintained properly.
Thread Starter
Drifting
Joined: Sep 2007
Posts: 1,442
Likes: 1
I just got back in from trying to get the bubble out of the system. This last time the temperature never even got high enough for the high speed fan. It went to 230 but quickly dropped to 221. I will try to go to work in the morning. If it overheats again I will install a new water pump.
How long does it take the average person to install the pump? Is there a write up on this cuz I can't find it? Can a waterpump be so intermittent like this?
Thanks for all the help.
How long does it take the average person to install the pump? Is there a write up on this cuz I can't find it? Can a waterpump be so intermittent like this?
Thanks for all the help.
Safety Car
Joined: Aug 2000
Posts: 4,933
Likes: 30
From: San Rafael CA
Try this ...
http://www.ls1howto.com/index.php?article=27
jump down to PART 2 ... you don't care about the wiring stuff as you're putting in a stock pump ...
Just use the instructions in Part 2 ... reverse them to install the new pump ...
Service Manual says on install, first pass at the water pump bolts torque to 11 ft/lb, second pass torque to 22 ft/lb. Remember to start ALL of the bolts BY HAND when installing the new pump, you DO NOT want to cross-thread any of these bolts by wrenching (forcing) them in. You may have to wiggle the new pump/gasket around to get the bolts to start .. but be sure they are all comfortably screwing in before taking a wrench (socket) to them.
http://www.ls1howto.com/index.php?article=27
jump down to PART 2 ... you don't care about the wiring stuff as you're putting in a stock pump ...
Just use the instructions in Part 2 ... reverse them to install the new pump ...
Service Manual says on install, first pass at the water pump bolts torque to 11 ft/lb, second pass torque to 22 ft/lb. Remember to start ALL of the bolts BY HAND when installing the new pump, you DO NOT want to cross-thread any of these bolts by wrenching (forcing) them in. You may have to wiggle the new pump/gasket around to get the bolts to start .. but be sure they are all comfortably screwing in before taking a wrench (socket) to them.
Last edited by BlackZ06; Oct 28, 2007 at 09:29 PM.
Safety Car
Joined: Aug 2000
Posts: 4,933
Likes: 30
From: San Rafael CA
Time to install ... hard to say exactly, but if you give yourself 4 hours ... you should be fine. The most time consuming is just getting enough stuff out of the way to get to the pump. Take apart as little as you need to. The "theoretical" quickest way to do it is to remove the serpentine belt, remove the air cleaner duct (air filter, air bridge and accordion hose), remove hoses from water pump, unbolt the pump .... of course this means when you pull the hoses/pump coolant will run all over the place as you haven't pre-drained the coolant, but if you don't care about the mess ... 
even that step can be skipped.
even that step can be skipped.
Thread Starter
Drifting
Joined: Sep 2007
Posts: 1,442
Likes: 1
Try this ...
http://www.ls1howto.com/index.php?article=27
jump down to PART 2 ... you don't care about the wiring stuff as you're putting in a stock pump ...
Just use the instructions in Part 2 ... reverse them to install the new pump ...
Service Manual says on install, first pass at the water pump bolts torque to 11 ft/lb, second pass torque to 22 ft/lb. Remember to start ALL of the bolts BY HAND when installing the new pump, you DO NOT want to cross-thread any of these bolts by wrenching (forcing) them in. You may have to wiggle the new pump/gasket around to get the bolts to start .. but be sure they are all comfortably screwing in before taking a wrench (socket) to them.
http://www.ls1howto.com/index.php?article=27
jump down to PART 2 ... you don't care about the wiring stuff as you're putting in a stock pump ...
Just use the instructions in Part 2 ... reverse them to install the new pump ...
Service Manual says on install, first pass at the water pump bolts torque to 11 ft/lb, second pass torque to 22 ft/lb. Remember to start ALL of the bolts BY HAND when installing the new pump, you DO NOT want to cross-thread any of these bolts by wrenching (forcing) them in. You may have to wiggle the new pump/gasket around to get the bolts to start .. but be sure they are all comfortably screwing in before taking a wrench (socket) to them.
Instructor
Joined: May 2006
Posts: 115
Likes: 0
mine did the same thing you are describing. take off the little hose that goes from the radiator to the throttle body. mine released a ton of air and the fluid level in the resivor went down a few inches. now my coolant temp never gets above 200.
Le Mans Master
Joined: Dec 2006
Posts: 7,251
Likes: 16
From: Phoenix Arizona
Le Mans Master
Joined: Dec 2006
Posts: 7,251
Likes: 16
From: Phoenix Arizona
a lot of the work is to the waterpump 
Safety Car
Joined: Aug 2000
Posts: 4,933
Likes: 30
From: San Rafael CA
That's great .... just keep an eye on the reservoir for a few days .... there may still be a little air that will now naturally clear out of the system, so you want to keep the reservoir "topped up" so no more air can get into the system.
Keep us posted.
Good luck,