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strange overheat:new water pump, thermostat and good radiator - SOLVED


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19 replies to this topic

#1 grossgary

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Posted 20 April 2006 - 04:01 PM

got this JDM motor and it starts to run hot.
the radiator/hoses don't get warm at all. the water pump side gets a little warm i think but the radiator for the most part stays cool.

brand new water pump, thermostat, hoses and no leaks. water pump is spinning when the engine is running.

the radiator appears good and flows fine with a garden hose flowing in one end. i inspected it off the car - hose on one end, comes out the other. so the radiator isn't the hold up.

when i pull the radiator cap or the hose at the thermostat and crank the motor - coolant doesn't come out. seems like the water pump isn't moving the coolant or something is major clogged internally? neither of those hardly seem possible though. even a bad water pump or clog would at least allow some water to get through?

anyone ever seen a new water pump that can't pump any water?

#2 Roundeye

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Posted 20 April 2006 - 04:50 PM

Are you SURE it's the right pump for that engine? If the impeller is too far away from the surface it runs against (front of engine), it won't pump.

If it is right, it sounds like you may have a restriction in the engine. You can try this: Remove the thermostat and pull the radiator hoses off at the radiator. Run water into the feed hose and see if it runs out of the return. This will tell you if the engine flows water.

How can the engine be clogged? If this is a used engine, it could have belonged to someone that pissed somebody off. Some instant rice in a radiator will pack the coolant passages when it gets hot. A long shot, but nothing can be ruled out at this point.

Pull the heater hose off of the top of the water pump with system full. Make sure coolant gushes out. (engine NOT running of course) This ensures the pump is primed and not cavitating.

#3 Silent Bob

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Posted 20 April 2006 - 06:18 PM

Did you make sure all the air was purged out of the system?

Fill radiator and start engine with the radiator cap OFF. Bring to operating temperature, adding coolant as necessary as the level drops. Make sure the heater control is on hot. Run until the level stays constant, and you stop seeing bubbles. Doesn't hurt to give the hoses a squeeze now and then to burp out the air.

Air in the system will make it run hot, regardless of new coolant/pump/thermostat etc.

#4 boozen

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Posted 20 April 2006 - 10:01 PM

I don't want to burst any hose's (no pun intended) but I have just experienced a overheating issue with my 85 wagon. It was none of the above mentioned items, unfortunately for me, it was a blown head. I don't wish the worst for you, but a blown head can be deceiving. The right head (passenger side), the last to get coolant is often the culpret. Someone here can tell you how to check this, I have yet to get this far.

#5 Frank B

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Posted 20 April 2006 - 10:32 PM

I second the air purging advice. I had it happen too many times. I fill the rad slowly while "pumping" the hoses, usually does the trick. Also filling the rad with the cap off of the flush tee helps to let the air out.

#6 grossgary

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Posted 21 April 2006 - 10:10 AM

thanks guys.

water pump - thought i got the right one, looked over multiple threads about the different pumps. if the belt fits right and lines up that doesnt' mean it's the right one? i thought only the shaft length/pulley styles were different?
funny thing - i bought the right water pump for an XT Turbo - but who knows what this JDM engine is on. can all the pulleys/belts line up perfect but it still be the wrong water pump?

anyway to verify i have the right water pump? think i chucked the old one.

pretty sure i got all the air out. did the fill, refill, squeeze the hose and all that jazz. but i'll try again. with system full i pulled the hose at the thermostat and not one drop came out with the engine running. water was sputtering/moving a tiny bit in the thermostat housing, but that could have just been engine vibrations/heat.

thanks

#7 mikeshoup

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Posted 21 April 2006 - 10:15 AM

Is the thermostat still in when you check for flow? Seems to me that the thermostat would closed, restricting flow out of the housing when its cold.

Even though its brand new, the thermostat could be stuck. Tried testing it with the old boiling water in a pan trick yet?

#8 grossgary

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Posted 21 April 2006 - 10:25 AM

thermostat tested fine in boiling water and was removed for testing so that's ruled out. good call, forgot to mention that.

#9 JWX

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Posted 21 April 2006 - 11:00 AM

take the hoses off the radiator, and run a garden hose thru the engine. kinda sounds clogged or something.

#10 grossgary

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Posted 21 April 2006 - 11:05 AM

i'll give the hose through the engine a try, will it come out even with the water pump bolted on or do i have to remove that?

anyone know if i could have the wrong pump installed? belts/pulleys all line up perfectly. are the impellers different?

#11 DrKrazy

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Posted 21 April 2006 - 11:33 AM

I think there is only the two different length ones, so I think your right on that. If you take the radiator hose off from the water pump and spin it does water come out the pipe? Also have you taken off the hoses going to the heater core and checked flow there? Seen a few clogged heater cores....defintely sounds strange.

#12 grossgary

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Posted 21 April 2006 - 11:34 AM

so the water pump is correct. that's nice news.

#13 RONAN

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Posted 22 April 2006 - 06:30 AM

A while back, I had a similar problem. It turned out that the water pump had a plastic impellar and after it started to warm up, for some reason the pump flow diminished. I changed to a metal impellar pump and the problem disappeared and has`nt come back.

#14 grossgary

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Posted 22 April 2006 - 06:56 PM

this is jacked up (also known as BS!!!)

plan is to pull the hoses, the water pump, heater core lines and see where water wants to flow and where it doesn't. and check the water pump out.

thanks again.

#15 DrKrazy

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Posted 22 April 2006 - 07:16 PM

Feel your pain Gary :-\ , make sure you let us know the results of your flow test. This is one of the more interesting problems I've seen in awhile.

I've never seen an EA82 water pump with a plastic impellar, if I ever did I would hand it right back. Plastic impellar in a pump that circulates super hot water and is bolted to an engine block...sounds scary.

#16 grossgary

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Posted 22 April 2006 - 07:19 PM

I've never seen an EA82 water pump with a plastic impellar, if I ever did I would hand it right back. Plastic impellar in a pump that circulates super hot water and is bolted to an engine block...sounds scary.

i'm with you on that one. i'd find it hard to believe that i would have not noticed. i looked at it a good bit since i wanted to make sure it was the right EA82 pump so i think i would have noticed if it was plastic, that would be too weird.

i'll post back for sure.

#17 NorthWet

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Posted 23 April 2006 - 12:59 AM

I, too, feel your pain. I have spent a lot of time that last couple of months chasing cooling system gremlins. I thought for sure that my sedan had either (a) blown head gasket or (B) a plugged radiator. Turns out that neither was quite true (I am replacing the radiator on general principle). I have had one instance of a sticky thermostat, and a lot of problems with air pockets. Every time I drain or lower the level of the water in the block, I spend 2 days trying to get coolant back in (drive, cool, topup, drive , cool...). I have pulled the radiator 6 times and the t-stat 3 times, and I am getting good at being patient.

I have also gone nuts with an XT that I just did HGs on that exhibited the same issues that you have mentioned, both before and after the HG replacement. Impatience may have cost me at least one HG...

I can't imagine that the water pumps are different except for shaft length needed to deal with A/C issues.

Another thought is, does the heater put out any heat? (Assuming that the engine can be run along enough to do this.) This would indicate whether your water pump was pumping and the heater core was flowing.

#18 grossgary

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Posted 23 April 2006 - 05:30 AM

Another thought is, does the heater put out any heat? (Assuming that the engine can be run along enough to do this.) This would indicate whether your water pump was pumping and the heater core was flowing.

if no water circulates through the radiator it seems coolant is not moving for some reason....but i can't remember if it had heat or not.

#19 TomRhere

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Posted 23 April 2006 - 07:57 AM

Strange one indeed... The only time I've seen an engine not circulate coolant was when I poured the anti-freeze in 1st and topped it off with water instead of mixing it before hand. The engine over heated, and the stuff never circulated.

Can't see how anything could get into the coolant passges to block flow totally. Although that rice thing sounds reasonable, I'm sure you would've noticed something like that when you pulled the old pump off though.

Even if, say a mouse could've gotten past the waterpump and built a nest in the block, there's more than one passageway thru the engine for coolant, and you'd have some flow, or atleast I'm thinking so. And yes, I have pulled/flushed a mouse nest out of an engine that sat without a freeze plug in it, (Chevy V8). Just don't see that happening on a Soob engine though, myself.

#20 grossgary

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Posted 28 April 2006 - 05:51 AM

head gasket.

water flowed through the engine fine. in the thermostat, out the water pump side. noticed while turning the crank that i could hear "swishing" through the open radiator hoses. not good....removed some spark plugs and see coolant in cyilnder 1. the bad news is that i installed a brand new intake manifold gasket before installing the motor so it has to be a head gasket. i'll check first, but most likely head gasket.

at least i found the problem. not what i wanted to find, but i can fix that.




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