Welcome to the DoItYourself Forums!

To post questions, help other DIYers and reduce advertising (like the one on your left), join our DIY community. It's free!

'86 Jimmy O'heats


Boeing Mech.'s Avatar
Visiting Guest

Posts: n/a

12-07-04, 07:10 PM   #1  
Boeing Mech.
'86 Jimmy O'heats

My full size Jimmy V8 305 runs fine at idle but when travelling around 45 mph, it starts to run hot and will overheat if you let it. When this happens, the heater also starts blowing cold. If you rev the engine, the temp. starts coming down and the heater blows hot again. I have replaced the thermostat twice.

 
Sponsored Links
davo's Avatar
Member

Join Date: Apr 2002
Posts: 2,417

12-08-04, 02:01 PM   #2  
Sounds like you have air in the cooling system and will need to run it with the cap off and burp the air out.Have you had a leak in the past or have one now?

 
Boeing Mech.'s Avatar
Visiting Guest

Posts: n/a

12-08-04, 08:59 PM   #3  
Boeing Mech.
I have not had the truck for very long. It did blow a heater hose early on. I suppose it could have gotten air in it then. I will try to purge the air out. Thanks!

 
Desi501's Avatar
Member

Join Date: Oct 2003
Posts: 2,207

12-09-04, 02:17 AM   #4  
If somebody tried to fix that heater core by putting sealer in it, you may have some restriction in there also.

 
bejay's Avatar
Member

Join Date: Dec 2001
Posts: 2,538

12-09-04, 04:04 AM   #5  
If the heater works good until the vehicle starts overheating it is probably just getting low on coolant from blowing some out the overflow.
suggest checking radiater for restriction, and fan clutch.

 
Search this Thread