My car has 57,000 on the existing water pump, my 2nd. When driving above 50 mph the temp will rise from 197...198....199...200....201...202...20 3...204...205... till I slow down to 40 or less then it will start going back the other way till it gets back to 197 - 198...Now it use to run the 197 - 198 all the time, until the past month. I have checked for debrie in front of the radiator and its clean. I can't see any fluid coming out of the weep hole on the water pump but I found some sort of fluid on the underside of my hood right above the serpentine belt where it turns downward almost right above the water pump. I suspect its a power steering leak but i haven't narrowed it down yet.
I don't know if this is associated with the leak but I have been getting an check engine light, it comes on for a few miles then goes off. Its off much longer than its on, I guess I need to go and see what it says at the auto parts store.
I am assuming that I have a water pump going out but someone else suggested it could be a thermostat and thougth I should change it out first...What do you think?

Thanks in Advance,

Boots

PS I called the local chevy dealer and they quoted me $680 to install a new water pump and hoses :eek: so I am probably gonna change the sucker myself if you think that is what it is... :smash: :smash:

 

I had a Trans Am once that I had to keep adding coolant, No visial signs of leaks either. I had a garage put a pressure check on the coolant system and sure enough it was leaking. I guess it was a small leak and evaporated due to the heat of the engine. Just my .02 worth.


[Modified by TALMADGE, 7:31 AM 12/11/2002]

 

Your thermostat may be stuck. If it is just cracked open it will cool until you work the engine then it would heat up slow down and it would cool. Since the thermostat is cheap I would try changing it first. If it is stuck you should notice the engine being slower to warm from cold start. If the coolant was low it would overheat and slowing down will not replace the lost fluid if it is full when you check it then a leak is not you problem. warm the engine remove radiator cap and rev engine to about 2500 rpm you should see cosiderable water flow if not either the stat is not fully open or the pump is bad. Replace the stat first


:cheers: :cheers:


[Modified by black bart, 8:00 AM 12/11/2002]

 

:iagree: Ditto on starting with the Thermostat!

 

Thanks guys, I will change the thermostat this evening and see if that helps.
I will know first thing tomorrow morning for sure then. :yesnod:

 

If engine is cool when you remove the thermostat and it is cracked open then you know you have found the problem. If not your not out much work or $$$$ :cheers:

 

My guess is your radiator is clogged. You can't see what crap is in the fins without removing it. Pulling it and cleaning it won't cost you anything but time and a gallon of coolant.

A pump doesn't move less water when it goes bad. Unless it's so bad that it sucks air through the bearing, but then you'd have a big pool of coolant on the ground.

 

Here's a what-if: What if one of your hoses is collapsing? Pop the hood, start 'er up and let it get up to operating temp and rev the engine up while watching the upper and lower rad hoses. Just a thought.

 

Your engine heats up at highway speeds because of inadequite flow. All the previous suggestions are good, new thermostat, collapsed hose, debris in radiator. Try blasting water backwards through your radiator, then around the radiator cap gap to flush the gunk out. When I installed a Stewart water pump which has higher flow, my engine doesn't heat up at highway speeds anymore. I knew I had flow rate problems with the original pump because at a stoplight I could race the engine and the coolant temp would fall. The Stewart doesn't do that. If all else fails, install a Stewart water pump.

 

Damn lots of great advise here :cheers: You guys makes lots of sense, glad I asked before I just changed the water pump out. I was gonna do the thermostat last night but after getting home and opening up the hood I decided to wait till I can get the upper and lower radiator hose so I can change it all out at one time.
I am gonna take everything off then take a hose and flush it down thru the radiator and see if I can get any crud or foreign material out before I change the hoses and thermostat. It makes sense that its something that is either limiting the flow of cooling fluid or the radiator is not cooling the coolant down enough. I am gonna go with the limiting the coolant flow because at lower speed the engine does cool down 5 to 7 degrees. IF it was the radiator it wouldn't cool down those 5 to 7 degrees as fast...

Does anyone of you think I should change out the temp sensors while I am at this? The digital and analog temp seem to be fairly close( at least from what I can tell, the analog is kinda hard to read since there is no making sense of the graduations marked out on the guage)

 

You'll have to pull the radiator to get it clean. Not a bad job since you are pulling the hoses anyway. I think there's a tech tip on doing the job. The most time consuming thing is actually cleaning it when you get it out.

I disagree with the flow theory. Cleaning the radiator has made huge differences on most cars that do it.

It's kind of like what doctors say. When you hear hoofbeats think horses not zebras.

I wouldn't bother with the sensors unless the gauges are stuck on either extreme of the gauge and don't move.


[Modified by John Row, 9:42 AM 12/12/2002]

 

Changeing the hoses is a good idea since you will have it drained anyway but I doubt if that is your problem hoses seldom collapse they have to be really bad. You can feel them and see how soft they are but I'm betting on a bad stat. As for the sensors if they ain't broke then don't fix them. What you may want to consider is put it togeather and just add water and a couple of cans of radiator flush drive it for about half hour then drain and flush good with water then replace with fresh coolant and all will be well again. :seeya

 

Ding Ding Ding Black Bart you were correct....Thanks :cheers: :cheers: :cheers: for the advice, I was just gonna change the water pump first.

 

YOUR WELCOME GLAD TO HELP :seeya

 

Change the thermostat first.

I spoke with the manufacturer of the thermostat and the man told me that thermostats tend to get "lazy" after about 50K miles and don't open fully. His recommendation was to change stats every 50K miles.

 

At that mileage "lime" will collect around the tube ends, restricting coolent flow and by all means check the thermostat and presure check the system. If the radiator is clogged get it rodded out and use a 50/50 mix of anti freese and DISTILLED water this will retard the formation of mineral deposits