overheat issue- please help

[onebadhabit]

Thanks in advance for assistance on this one. Just seeing if anyone has had similar issues.

Model 620i Engine hours: 188
Cranked and let it warm up a few minutes while I was loading my spray tank.
After starting thru the yard spraying weeds the fan kicks in and the overheat light starts flashing. Check the radiator by touch and it doesn't seem that hot and notice the overflow tank is full and then some. I did take it out to the street and ran it a little faster to get some air thru radiator. That worked for a little while....Came down to running for 5 minutes until light came on and then shut down and run the fan only to cool off.This went on about about 5 more times

Here's my thoughts:
- the fan did not sound that strong when it came on, but it was pulling air, but it did seem to get faster when I gave it gas at idle- possible fan or alternator or battery? i put battery on charger to top it off
- thermostat could be sticking- have not checked it

Longshot:
- bad/old/contaminated gas causing improper detonation and overheat- it will idle fine, but does have some hesitation- I need to clean TB and replace fuel filter


At a loss after that.

Thanks,

Chris

[onebadhabit]

Checked a couple other things. The water return canister, or whatever the thing with pipes going into it before water pump is getting hot. Also noticed when cranked the water rises in radiator and doesn't drop.

[onebadhabit]

removed plug at engine to make sure water was in block. its fine. Let her idle for a few minutes and engine got hot, but did not seem to change at radiator. Where is the Tstat on these engines?

[fire gator]

could have air pocket in cooling system

[Regulator]

could have air pocket in cooling system

That definitely could be....I'm betting that the thermostat has shit the bed though...if the engine is getting hot, but the water in the radiator is staying cold, then it's simply not circulating...an air pocket will do that or a faulty thermostat...if someone on here more knowledgeable than me doesn't tell you where it's located, you better go to the Dealership and find out where it's at and get a new one just in case...

After re-reading your comments, I am kinda confused...the tank is sim ply an overflow tank that the radiator uses so that water doesn't blow out on the ground if the level rises too much under pressure....so, the water level in the radiator shouldn't rise and fall too much because it's either sucking water out of the overflow tank, or pushing it into it...if the water in the radiator is cold, then I still think the thermostat is bad...I am really interested in what it ends up being, so please keep us informed...

Sorry I can't be anymore help than that....

Larry in MD :Jestr:

[osiris]

[QUOTE=Regulator;22148]....I'm betting that the thermostat has shit the bed though...
:IAgre:
when u find the thermostat and pull it out u can test it by putting it in a small pot of boiling water and it should open up therefore allowing coolant to flow to the radiator and when it cools back down the thermostat will close again..also if the thermostat checks out alright when u have the thermostat out u could crank it over for a second and see if it pumps out coolant to verify the water pump is working correctly, im sure theres better way to test the pump just not that im aware of but i bet someone else will have another idea, good luck

[onebadhabit]

That definitely could be....I'm betting that the thermostat has shit the bed though...if the engine is getting hot, but the water in the radiator is staying cold, then it's simply not circulating...an air pocket will do that or a faulty thermostat...if someone on here more knowledgeable than me doesn't tell you where it's located, you better go to the Dealership and find out where it's at and get a new one just in case...

After re-reading your comments, I am kinda confused...the tank is sim ply an overflow tank that the radiator uses so that water doesn't blow out on the ground if the level rises too much under pressure....so, the water level in the radiator shouldn't rise and fall too much because it's either sucking water out of the overflow tank, or pushing it into it...if the water in the radiator is cold, then I still think the thermostat is bad...I am really interested in what it ends up being, so please keep us informed...

Sorry I can't be anymore help than that....

Larry in MD :Jestr:

Guess what I was trying to say is remember back in the day when working on cars with your dad or grandad in my case, how they would always say to check the tsats were to remove cap and let the engine warm up. Once the water started flowing it was like a river circulating around. Thats all I was trying to say.

I removed the top cap on the motor to bleed the air out of the system so I can scratch that.

I'm thinking the tstat is in that, let's call it, "distribution canister" (hope some of you are Austin Powers fans) since the large radiator hose goes to that point and several pipes branch off and go around the engine.

[GATORDONE]

Follow the r.h. radiator hose and it will connect to the thermostat housing, It has three bolts holding the halves together.