1.9td over heating

[vee-mac]

hi i have a 1997 1.9L td that loves to over heat on the hwy at the high speeds. its had its theromstat changed, as well they have replaced many coolent pipes, and they say the cooling system is working 100%. I realize that the car only overheats when driving around 140kph, for an extended period of time....do these engines just create to much heat at this speed, or am i missing a common problem....any help would be great, as well any aftermarket ideas for extra cooling?

[jtanguay]

i'm having the same exact problem.

i'm pretty sure that it is the water pump.

[jannemann]

hi, it`s a well known problem of the turbo-engines. They like to overheat. It`s nearly a duty to install a good oil-cooler. The dimensions of the chanells of water aod oil in the block are too small. Mistake of construction. Highspeed orgians on the highway are a good method to kill an engine...

Regards from Germany Jan

[jimfoo]

Not that they aren't small already, but do water pump pulleys come in different sizes, or crank pulleys for that matter? Faster water flow=more cooling.

[addautomotive]

This thread should really be in the "troubleshooting" forum

FWIW, overheating on the highway IS NOT typical of these engines. I can drive 140km/hr for hours on end, and my temp guage always sits just below the 1/2 mark. It's the same in -25*C January and +25*C July.

I'd suspect your water pump or radiator.

[jannemann]

Unlikely, the water pumps are said to be growing old, but two of my friends had engine damages because of over heating (1,6 td , SB and JX) in VW busses. One was repairable the other was not. The water pumps and the rest of the cooling system was ok. When AAz engines overheat, the injection chambers (I hope this is the correct word) like to fall into the cylindres. I saw two engines with this damage. But I don`t work in a garage..I`m a music teacher :lol:
to your case: 140 km/h isn`t really top speed for an AAZ -Jetta, isn` it?  :wink:

Jan

[jtanguay]

well i know for sure that if the cooling system was working properly, my radiator would be getting the hot coolant passing through it.

at the current moment that is not happening.  otherwise the thermoswitch in my radiator would be going off and the engine temp would be cool.

however, at idle the car's temp is perfect, fan kicks on when it should (in the middle of the 1/2 and 2/3 mark).

so that is a big mystery to me...  and it clearly leads me to believe that my water pump impeller is slipping at high revolution (my car runs at about 3000-3200 rpm on the highway) but at low revolution it seems to be working just fine!

I must agree about the fact that the turbo does create a lot of heat... and is a main cause for breakdowns.  If my radiator fan was coming on at highway speeds, and my car was STILL overheating, then yes I would wholeheartedly agree with you!!

[stopping]

Well I just did a search for 1.9 gasket and found this thread.

No has yet to mention cavitation around the blades of the water pump as a reason.
I have a similar trouble in that I can't driver the engine too hard or it will get too hot. I was thinking it is a head gasket issue... only leaking when the engine get really hot. It could still be a head issue but the cause of over heating could be elsewhere.

How about slowing the water pump (larger pulley) and adding a oil cooler?

[jtanguay]

Well I just did a search for 1.9 gasket and found this thread.

No has yet to mention cavitation around the blades of the water pump as a reason.
I have a similar trouble in that I can't driver the engine too hard or it will get too hot. I was thinking it is a head gasket issue... only leaking when the engine get really hot. It could still be a head issue but the cause of over heating could be elsewhere.

How about slowing the water pump (larger pulley) and adding a oil cooler?

hmmm i wouldn't touch the pulley... just add the oil cooler and that should be ok.

i think i just had a really neat idea... we have oil pressure gauges, fuel pressure.. why not coolant pressure?  i think i may rig something up in the near future!  if my psi is going up like my boost gauge then we'll know whats going on  :lol: but i do have a metal HG in there which should avert any problems.

[vixentd]

Mine started doing the same thing after a new motor was installed. Did everything you did, including a new thermostat.  I even replaced the voltage reg in the dash to make sure the gauge was accurate.

There is a large relay on the drivers side just behind the battery that controls the fans and a number of wires going in. I swapped that out and my guage stays right in the middle now. NOt sure how the wiring goes but i think it somehow was effecting the guage reading and i never really was driving hot.

That gauge is dependent on the exact voltage.  On my other passat diesel I could tell the voltage reg was off as the gas gauge would fluctuate, ie it would show a bit more fuel whenever it showed warmer.  New voltage regulator solved the problem.

Timing can also cause it to run hot.