Going to and from work my water temp is always at normal operating range. As soon as I park my car for more than 5 minutes, hop in it and drive it again the temp goes up a bit and continues to go up until I get to highway speeds it cools off due to air circulation. Ive noticed that if I let my car idle in the drive way to get to operating temp and I have the heater on, it wont pump out hot air until I give it gas.

Last month I changed my thermostat and flushed the system including the heater core. Since last summer my heater hasnt really worked much, have had to constantly flush the heater core. Im starting to think that the water pump being out has caused some blockage in the heater core.

I have a feeling that my water pump is going out and will be checking tomorrow. Any ideas on what could be going on?

Thanks in advance!

 

Unless the impeller has erroded away, I seriously doubt the pump is bad. I have only seen it happen once in 30 years of swinging wrenches.

I believe you probably have air in the system. I install a cleanout "T" in the heater hoses to allow me to bleed the air easier.

 

not waterpump

 

I have one of those installed already and have bled the system as best as I can. I have tried doing that several times as well.

 

Definately sounds like you have air in the system, and or your coolant is low. If it's circulating (blowing hot air when you press the accelerator) then your pump is in fact working Changing the thermostat would have little effect on your heat issues though. The heater is plumbed in before the t-stat.

The overheating issues could be attributed to a bad t-stat, but if it's only a month old........

Have you noticed a loss of coolant since you changed it?

I changed the water pump in my Blazer last week, and although I don't have a 'tee' in my heater hoses, I had very little problems bleeding the air out of the system. Maybe I just got lucky



Aaron

 

I would actually take a closer look at the fan clutch as well as the radiator/condenser exterior. Clean the radiator & condenser as best you can with a hose to ensure maximum cooling efficiency. The fan clutch should lock up when the radiator is hot. Right after you shut the truck off after everything is up to operating temperature, the fan should have a good amount of resistance if you were to try to turn it.

 

The most frequent failure point of the water pump is the shaft bushing. When it starts going bad coolant will leak from the weep hole along the shaft. it rare for the impeller to go bad as they are very heavy duty and don't usually wear out.

The temperature rising after sitting for 5 minutes is normal as the engine is still hot and nothing is cooling it except for ambient air. it should, however, return to normal a short time after you get going again....at any speed. if not then like Swartikk said check your fan clutch to ensure it's not freewheeling and check the radiator for debris that can block the air flow. Beyond that the other's are correct in checking for air in the system. Swartikk is a proponent of raising the front of the car and running it will the radiator cap off to let it burp. I thought he was joking with me when I first joined here...sort of like when I was an air traffic controller and was told to go find some flight line or a bucket of prop wash.

 

Im starting to wonder if it is my fan clutch. I noticed not too long ago that if you were to spin the fan by hand it goes without ease, from my recent understanding, that shouldnt happen, it should only turn a bit if at all. Could this be a possibility as to my engine over heating?

Also a noise that I havent noted yet is when it does get hot it starts to sound like an airplane. This always happens at 210 degrees and up. If I remember right my Tstat is set for 185.

I noticed earlier when I looked under the hood of my car that the return hose to the radiator was flat and as soon as opened the radiator cap it returned to normal. Is there a reason for that?

I appreciate all this help, its saving me a lot of money, by now I would have popped a new WP on and called it good until I realized something else was wrong.

**EDIT**
I just went out to test the fan and at first if I were to grab a blade and flick it, it would go about 1/8th of a turn and it would stop. After some working with it, it 'loosened' and started to spin with ease in either direction.

 

Your hoses should not collapse. Replace them. When there is a vacuum in the system, it should pull the coolant in from the overflow.

 

Some updates, after some searching on the internet ive begun to wonder more and more. Lately when I get up to highway speeds the noise is still present but not nearly as loud as it would be when I am at city speeds (30-45). I However am still wondering about why my blazer is still overheating. Can collapsed hoses be the cause of this? I know for a fact that no coolant is being pulled from the overflow.

I am having quite a hard time pinpointing the causes of these issues. I cant tell if these are separate issues or one and the same. I do know that when the car gets hot (210+) is when the loud fan noise kicks in and I reach highway speeds, it only drops maybe 5-10 degrees. Almost as if nothing is getting cooled off. Im debating whether or not I should replace the hose first or the fan clutch or both.