Author Topic: overheating 85 vw (Read 4763 times)

Duster 5.9 · « **on:** October 05, 2008, 05:37:38 pm »

ok my father is having a running hot issue with his 85 jetta and his 85 golf. i don't have the bently for the 85 and later so i'm asking. both cars run hot while the lower rad. hose is cool, why? change thermostat in both cars. even swapped in a used rad. does anyone have the flow chart for these as in dirrection? while driving he explains that the temp will go way up and the car runs funny, but still the lower hose is cool. he thinks the pump is not pumping enough? i personally don't agree with this as there is a steady stream through the small haose going to the overflow tank. also note that the oil pressure light flashes. any idea's?

burn_your_money · « **Reply #1 on:** October 05, 2008, 06:40:20 pm »

I know it's a mk3 but it's basically the same thing

Duster 5.9 · « **Reply #2 on:** October 05, 2008, 06:50:49 pm »

i just had the golf running for abut 10 min in the garage. had a gauge stuck into the top of the resovoir. it got to 180. i had the throttle propped open a bit too. every thing was hot, except the bottom half of rad. even the thermostat cover was cool. the number 9 hose in your pic indicates to me that the warm coolant should be flowing across the thermostat? the in car temp gauge read half way. so this so far indicates to me every thing is ok and the stat just didn't open yet. i'm going for a road trip after i boil the stat i just removed to verify that one was working.

Duster 5.9 · « **Reply #3 on:** October 05, 2008, 07:35:42 pm »

ok the stat i boiled opened at 195 so it is ok. the stat i currently have in the car is a 185. i went for a 10 mile ride. the inside temp guage stayed right in the middle. when i got back the bottom rad hose was still cold. i quickly and carefully opened the rad cap and checked the temp, engine still running. at that point i had 188 degree's. i quickly again felt the lower rad hose and sure enogh the stat opened and it was warm.
so here is my theory: :roll: the rad my father changed could have been bad? upon putting in the used replacement, it could have gotten vapor locked. or air pocket.
every thing seems ok as of right now, i will further test it and consult w/ him on the issue. if i find something else i will surely post. now i just have to track down why the oil light flashes irregularily.

the caveman · « **Reply #4 on:** October 06, 2008, 10:56:47 am »

Make sure you got all the air pockets out. As it's getting warm the 2 hoses to the heater [# 1&2 in the picture] should get warm/hot almost right away. Pull one off and rev the motor until coolant runs out. Re-attach it, get inside the car, you should get warm/hot air. If it's staying cold, there's still air. The heater is basically the same height as the overflow bottle ,so it's easy for air to get trapped there. I used to have the exact same problem any time i opened the cooling system of a B3 passat.

Duster 5.9 · « **Reply #5 on:** October 06, 2008, 01:05:08 pm »

thanks for that insight, on my journey last night the heater worked real good, so that should be fine.