Overheating Problem any Suggestions?

stimo

stimo

cnc machinist/programmer
Joined
May 1, 2008
Messages
279
For some darn reason truck is overheating. I do have a electric water pump and I removed it and it works fine. I just changed thermostat to see if that would change anything and it did not. I poured coolant down where the thermostat is and it came out the water pump hole which I thought should be normal. So I took it for a spin and came back and temp was at 210 and not dropping at all. Top radiator hose was hot and bottom radiator hose was cold. So could something be plugged or what am I missing here?
 
What degree T stat did you put in? Do you have a winter front on? Did it start this all of a sudden?

Most T stat's are 190* units, add in a bit of gauge inaccuracy and you have a 210* reading, so are you getting a reading from the dash or from a standalone gauge?
 
I bought a 190 stat. There is no winter front on. And yes it started all of a sudden and actually it did not stop at 210. it was actually still rising but I just shut it down. And it is the reading from the dash temp gauge.
 
My old t-stat did the same thing but I just put the new one in to see if it would cure the problem but no luck. Also truck has been sitting for the last 3 months.
 
Get a laser/temp probe and see how the coolant is flowing in your radiator. A previous owner could have added some kind of stop leak additive that clouded up your radiator? I don't know anything about the electric water pumps.
 
The radiator was just recently cleaned a couple of months ago due to blown headgasket and I had a lot of oil mixed in the coolant.
 
I just did some more dinking with this thing and now noticed while it running the bottom radiator hose had really no pressure in it becuase I could squeeze it shut which I don't think is right.:bang


Also if it could have got air lock in it how would you try to get that out?
 
Try this, put a bucket under the drain for the radiator. Open said drain and remove the radiator cap. Walk away for about 30 minutes. When you come back if the cooling system was filled to capacity you should have over 4 gallons of mixture in the bucket. Remember that you DO NOT fill the cooling system on these trucks with the truck running.

Something else to try while you have the system drained, remove both upper and lower hoses from the radiator and stick a water hose in the top port, see what kind of flow you are getting through there. The bottom hose should be cooler than the top hose but should still have pressure on it. If you popped a HG and got a bunch of crud in the cooling system it might have broken loose inside the engine block and made it's way to the radiator. With the problem coming on suddenly it kinda has me wondering.

The only other thing tat comes to mind is the pump is not pumping.
 
I did drain the system already and pulled water pump off just to make sure its working and it worked fine. I did drain around 4 gallons out of it also and put it all back in.
 
The pump can turn, but is it working under load? I've seen many DC motors that will run just fine until a load is applied. Get in touch with the folks you bought the pump from and see if they can give you any idea how to flow test it or somesuch, from the sound of things you either have very low coolant flow through the radiator or a water pump that is not doing it's job.
 
Finally got this thing narrowed down. I hooked the water pump directly from the battery and It flows fine even through the radiator. I just removed thermostat to make sure everything flowed correctly. So then I fired truck up and water pump was not working. Then messed around with the wiring and it worked but it keeps working and not working. So it must be the relay or something in the wiring.
 
Glad to hear you are at least on track to get it fixed, and when you find that electrical gremlin? I recommend a BFH :D
 
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