1997 Volkswagen Jetta Overheating

Tiny
MLHOPE
  • MEMBER
  • 1997 VOLKSWAGEN JETTA
  • 4 CYL
  • 2WD
  • MANUAL
  • 121,000 MILES
Coolant was leaking from the top heater hose where it connects to the engine. I removed the hose trimmed the end and reattached it losing a small amount of coolant in the process. I topped off the coolant in the reservoir and drove about 10 minutes before the car overheated. This car had never overheated before. I also had no heat coming from the heater. I was told I may have air in the system. I decided to drain the system and replace the coolant. Jetta has no drain plug on the radiator. I removed the bottom radiator hose, drained and flushed the radiator. I replaced the hose and attempted to refill the system through the coolant bottle. Jetta radiator has no cap. The coolant would not go into the system till I removed the top radiator hose to allow air to escape. I filled till coolant came out the top hose, then reattached the hose. The car is still overheating, and no heat from heater. I was told to alternate the car between idle and 2500 rpm for 20 minutes with the coolant bottle cap off and no pressure on the system till the air bled off. I did this and the heater began blowing hot air, the heat gauge was in the normal position of 190 degrees, but the engine was so hot the oil light came on! I am at a loss as what to do next. Help?
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Monday, October 27th, 2008 AT 5:20 PM

3 Replies

Tiny
RASMATAZ
  • MEMBER
Run it w/o the thermostat and tell me what happened this is where we start-get back soon so that we can continue. Or do below

Have it block and pressure tested-do the block first to pinpoint a combustion leaking into the cooling system or a gas analyzer to sniff for hydrocarbons at the radiator fill neck.

Pressure test: do not do a pressure test if there's leakage at the headgasket this might cause coolant into the cylinders and lock it up or bend a connecting rod if cranked thereafter. The headgasket should be repaired before doing the pressure test.

If the block and pressure test passes check the following:, Pressure test the Rad. Cap, Clogged radiator, air lock in the cooling system, Fan clutch, Radiator electrical fan, collaspe hoses, water pump.
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Monday, October 27th, 2008 AT 6:11 PM
Tiny
MLHOPE
  • MEMBER
To access the thermostat, it is necessary to remove the power steering unit and fan belt. I would rather not do this. When I removed the heater hose and replaced it, I introduced air into the system. My research tells me Jetta is notorious for this problem, but finding fixes is difficult. Lets assume the problem is air in the system. How do I get it out? Jetta has no drain plug and no radiator cap.
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Monday, October 27th, 2008 AT 6:50 PM
Tiny
RASMATAZ
  • MEMBER
When refilling the cooling system, air can become trapped under the thermostat. This will form a steam pocket that prevents the thermostat from opening and may cause the engine to overheat. Some cooling systems have one or more bleeder valves that can be opened to vent air from the system while refilling the system. If your cooling system does not have a bleeder valve, you can drill a small hole in the thermostat as shown. This will allow air to escape past the thermostat so it is not trapped inside the engine block. Some thermostats come with a similar feature called a "jiggle valve." There is a small hole in the thermostat with a pin that allows air to escape.


http://www.2carpros.com/forum/automotive_pictures/12900_thermostat_bleedhole_1.jpg

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Monday, October 27th, 2008 AT 7:00 PM

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