Overheating and oil problems

[laser030]

Recently my NA 1.6L jetta has been having large problems with overheating, while the warning light has never come on (always stopped it ~7/8 way by kicking on the heat) it is getting very annoying.  I was wondering if a turbo radiator, or another option is available.  Also wondering what people have tried as far as upgraded fans, the stock fan is not moving very much air.

Now the oil problem.  When going up hill during one of these higher heat periods the oil warning will buzz one time only.  Never continues, just one quick buzz and flash, until today when I got 3 out of it, was doing 65mph up a 4.5% grade hill when it went off.  Check the oil level, it is actually slightly high, 15-40 weight oil, about 1k left until the next change.  Any ideas??

Thanks for the help.

[BlackTieTD]

regarding the coolant temps problem... try to find out why your temps are so high... bad thermostat? i never saw above about 5/8 on my 1.5l NA and that was with a blown head gasket. you should be fine with the stock rad, i think your problem is somewhere else.

furthermore...

i'm still running the stock 1982 NA rad in my car, but now with a 1.6l TD engine from a 1990 jetta, and the temps are actually the same or even lower overall then when the 1.5l NA was in there.

[VWRacer]

Laser030, a couple of things come to mind. First, is your rad fan working correctly? By that I mean is the fan coming on as the water heats up? If not, you could have a bad temp sender or fan relay. Assuming the fan is cycling on and off correctly, the other thing I'd look at is the insides of the radiator itself. If hard water has been used in the rad it will build up mineral deposits which can block water flow through it. This can definitely affect the temp which the fan can maintain (no matter how hard the fan works!). If there are mineral deposits inside the rad, you may need to have the rad cored and cleaned. Check rad shops in your area to find out how much this will cost. Compare their costs to what a new rad will cost. Sometimes a brand new rad is actually cheaper than a rebuild.

Take it to a rad shop and ask them to inspect it. They will usually do this for free - but ask before committing to any work.

Good luck! Stan

[VWRacer]

I forgot to add a few comments about the oil pressure. There are several factors which can lead to low indicated oil pressure. First, the oil pump can wear internally, resulting in too-large clearances. Then as the oil heats up and thins out it shows as low indicated pressure, even under load. If the main or rod bearings are worn, that too will show up as low pressure, though normally at idle in my experience.

OTOH, with the oil weight you're running and at the fill level you indicate, I would not normally suspect oil pick-up problems. A 4.5% slope is not enough to worry about, even on long up-hill runs. From the sounds of it, I would guess that your engine is simply old and worn out. If rebuilding it is not practical right now, my best advice is to slow down on hills and run the defroster with the windows open any time the rad temps creep up too high.

Good luck! Stan

[type53b_gtd]

Recently my NA 1.6L jetta has been having large problems with overheating, while the warning light has never come on (always stopped it ~7/8 way by kicking on the heat) it is getting very annoying.  I was wondering if a turbo radiator, or another option is available.  Also wondering what people have tried as far as upgraded fans, the stock fan is not moving very much air.

Under what conditions does this occur?  If you see this while travelling at speed on the highway, suspect a faulty guage, sender or egine ground, along with a blocked radiator or faulty (closed) thermostat.

If it occurs while you're idling in traffic, then suspect a faulty fan thermoswitch (located in the rad) fan fuse, fan relay, fan, or fan wiring.

Now the oil problem.  When going up hill during one of these higher heat periods the oil warning will buzz one time only.  Never continues, just one quick buzz and flash, until today when I got 3 out of it, was doing 65mph up a 4.5% grade hill when it went off.  Check the oil level, it is actually slightly high, 15-40 weight oil, about 1k left until the next change.  Any ideas??

I would checlk the wiring for your oil pressure senders - it's likely that one of them is loose, or shorting, when you go up a hill or the engine torques.  It's also quite possible that the dynamic oil pressure control unit, which is tucked in around your speedo inside the instrument cluster, is faulty - this is not unusal.  It is best to verify oil pressure with a mechanical guage (in case it's oil pump/pickup related) but my guess is you've got a wiring/sender issue.

Drew

[laser030]

So, I replaced the fan switch for the radiator fan, and when I was doing that, a bunch of thick gray-brown sludge came out of the lower radiator hose. Flushed it out with a ton of water, refilled with proper coolant mixture, and now it overheats (>5/8 of gauge) even at hiway speeds, but the radiator fan kicks on low when the gauge reads (~7/8), which would indicate that the gauge may be incorrect.  

Does anyone know how to test this sensor?
Resistances at certain temps, my Bentley's has nothing.

Thanks

[BlackTieTD]

cant help you there, but id call up my parts guy and see how much that sensor is new anyway... might be an $8 or $10 fix, might as well

[type53b_gtd]

now it overheats (>5/8 of gauge) even at hiway speeds, but the radiator fan kicks on low when the gauge reads (~7/8), which would indicate that the gauge may be incorrect.  

By overheats do you mean that the light flashes?  

The guages are not overly accurate, so results may vary from one car to the next, but you gfenerally would expect the low speed fan to come on around 3/4 scale on the, give or take.

What year is the car?  On A1's and early A2s with coolant level indicators the control unit on the relay plate is known to fail, causing the lcoolant warning light to flash for the fun of it.

Another thing to check for is small coolant leaks in the system that would lower the pressure of the coolant - this will raise the temperature above normal.  Does the system  build and hold pressure when it is running?  For example, when the engine is warmed up fully, does the upper rad hose feel firm when you squeeze it (how rude does THAT sound? )

Drew