Mrmerlin

to test the coolant you need the engine running and the tester plugged into the coolant bottle,
fresh hydrocarbons will be released into the coolant if you have a questionable headgasket or cracked head or block
FWIW the earlier cars will need new headgaskets you can spot along the top edge of the gasket see if find crusty white deposits along the V where the block and head meet

nc_growler

Mr Merlin and many of the others that have weighed in already here helped me with a problem of overheating car right after replacing a WP last year.

I spent a couple of weeks squeezing hoses, playing with flow, coolant, thermostat, etc. all not wanting to believe that the previous WP that had failed at 1500 miles had been replaced with a WP that could fail within 24 hours of installation.

In the end, it was the WP.

Are you handy with wrenches? It's not as bad as it sounds. Lots of good threads out there, dwayne's is excellent.

I'm not saying it's your pump, but it certainly is beginning to sound like it.

Formula94lt1

Gotcha, found it at Oreilly for 42.99.

Anyone have recommendations on how to back flush the radiator now that its out anyways?

hacker-pschorr

Just flow water in the reverse direction it usually flows. A lot of the debris will be stuck to the fins unable to pass through the core on the inlet side. I've always just used an open hose, no pressure. Not sure a concentrated stream from a pressure nozzle is the best idea.

It doesn't take much to clog one of these.

I agree with the others you probably have something else going on, but as long as the radiator is already out, might as well give it a good cleaning.

Mrmerlin

back flush the outside as well revese flow the water back to front to remove all of the stones

Landseer

You might use a shopvac to help when flushing the insides.

mark kibort

you want to put your hand on the face of the radiator, without the fans blowing. see it if is hot, end to end, top to bottom. the radiators dont clog that easily, an entire side would have to be clogged. all the little paths on the radiator run side to side in parallel. you can have a few clogged and it doesnt effect the radiator. the end tanks are big and so are the openings to the engine.

you want to narrow things down before you start yanking T-stats and radiators.

Simple flow tests can determine if the pump is bad . ( i mentioned how you can short circuite the t-stat and replace to check the pump and the t-stat itself which is actually two tests)

If you have the radiator off, you can just hook a hose to the bottom and send water in reverse flow . is lots of stuff comes out, you might have a clogged radiator.

How long does the engine take to overheat? if it s less than 5 miles, you might have a pump problem. (or tstat). if the fans come on and its overheating too, then it could be the radiator being clogged.

Formula94lt1

If I turn the car on from a cold start it could idle for atleast 15 minutes or so before it got close to the 2nd white line, if I go for a drive it would take maybe about 5-8 minutes or so to overheat. BTW I have a viscous fan and it does work well.

I felt as much of the rad as I could touch and it was mostly cool except for a short portion of the top of the rad near the inlet. The air being blown out by the fan was however warm air.

BTW I do not know what flow test you are referring to..?

Mrmerlin

-to do that test of the rad you need to remove the fan belt

Formula94lt1

Hahaha I think that would quickly become clear! I actually meant the test for the w-pump and t-stat flow.

Thanks guys!

mark kibort

so, it takes too long to overheat if the pump was dead, but it could be slipping. whent it overheats initialy (near 2nd white line), if you turn it off and wait about 1 mins, and then turn it back on, what happens? sometimes if you have a sticking t-stat this will open it up, or if there is air in the system it will allow for some heating of the tstat so it opens.

the flow test is this. pull the t-stat and put a little colar over the shaft of the moving valve part. what we are trying to do is wedge it way open, so it stays open. you push the t-stat way open, and put this colar over the shaft, so when you re insert the pin on the valve, it cant close like normal. this forces and keeps the valve open. the colar can be a small spur gear from an electric motor, or just drill a hole through some piece of metal and put the pin through it, and then through the normal hole on the t-stat. Then, re-assemble and drive, now that you know that the t-stat is wide open, if it overheats again, you know its pump or radiator.

next, the flow test. or first, you can do this. take the lower hose off the t-stat assembly and hold it up with a bungie cord or something. you are going to be pouring water from hose into it, as you start the car up. the water exiting the t-stat housing should be fitted with an old hose, so thats where engine water will come out. start the car, have the hose pouring water in the existing lower radiator hose. the water level in the hose should be almost outpacing a slow flow from the hose. if it is stagnant, then its water pump or radiator. next would be to disconnect the upper radiator hose and use that to fill the water with the hose. you now have removed the radiator from the equation. if it sucks in and you have to pace the flow with the hose, pump is fine. rev the engine with throttle blips, while filling the hose. with higher revs the water requirements will be higher.
you can get fancy and get some clear tubing and connect the upper and lower hoses and watch flow from the start , which tells a lot too. all this needs to be done with the t-stat modification.
after you are done, you just pull the t-stat again and remove the spacer/fitting/colar, and put things back to normal. if you drive the car with the t-stat modified, it will and should take a lot longer for the engine to heat up.

Formula94lt1

I took the radiator to a friends house and poored water from a hose the opposite direction and nothing but clear water poored out. Honestly the radiator looks clean only a thin amount of grey slime at the exit and spotless at the inlet.Im in an apartement garage so no water hose. I just confirmed that my previous thermostat was good and since the installation of the new thermostat and seals changed nothing I feel ok to assume that all is still well in that area. Next I will go buy a coolant exhaust gas tester thing and make sure its not a head gasket. Then I will simply buy a damn pump.

Imo000

Don't buy a pump untill the existing one removed.

If the rediator is cold, then there is no circulation. If there is no circulation, it's not the head gasket, or a cracked block/head.

Formula94lt1

I agree, the radiator fan is blowing out warm air from behind the radiator. Testing the combustion gases tomorrow just to absolutely check that issue off my list.

Imo000

It should be a lot more than just war. If the engine is at the last white line or above, the air passing by the fan shoudl feel like a blast furnace.

Does the hose entering the thermostat housing feels cold? If it does, either the thermostat is stuck closed or the pump is not pumping.