Low Oil Pressure and Coolant Light

[SChizzle]

I have a 2001 1.8T VW New Beetle. My coolant light always comes even after long periods of driving. I refill it with a little water and it goes off, but then goes on after driving it for a bit. It’s never gone off this much before.. is it just a faulty gauge? Also, my low oil pressure light always comes on too, but only when I’m slowing down and going downhill. These lights have been going on for a couple months and I was told if I really did have low oil pressure my car already would have broken down and I would have noticed it by the way my car drove. I also hit a big rock before my low oil pressure light came on, would that have anything to do with it? I do regular oil changes every 3k miles with Mobile1 5W-30 for high mileage (my beetle is at about 128k). The light still came on after doing an oil change. I don’t know where the sensor would be and if this is a serious problem and if I should be worried or not?

[Design]

what color is the coolant light red or blue?

if you are constantly adding even a little fluid you have a leak you need to track down. An easy test is to find a large sheet of cardboard and place it under your engine after you drive it next. If you can see and drips it will help you narrow down your search for the leak. With as many miles as your car has the hoses, especially the convoluted upper coolant hoses, are suspect. However if you haven't replaced the water pump (and timing belt) that would be my second guess.

for the oil pressure, climb under your car and look for damage from the "big rock". There is probably a big dent in your oil pan. if so then you may need a new pan, oil pick up tube (on the inside) and of coarse gasket. Look for leaks if there was an impact.

[Smileybug]

I would replace the coolant temp sensor. I've read a number of threads where a faulty sensor sets both of the lights off.

[FootScoot]

Coolant temp sensor will set off both lights. On mine the coolant light stayed blue, and the oil pressure light would flash on and off, plus that annoying warning beep. Changed the sensor (1/2 hour job at the most) no more lights.

Do figure out where the coolant leak is coming from. I have a hose on the back side of my engine that seeps, but just needs a new clamp.

[MyOtherRidesAVette]

Originally Posted by SChizzle

I have a 2001 1.8T VW New Beetle. My coolant light always comes even after long periods of driving. I refill it with a little water and it goes off, but then goes on after driving it for a bit. It’s never gone off this much before.. is it just a faulty gauge? Also, my low oil pressure light always comes on too, but only when I’m slowing down and going downhill. These lights have been going on for a couple months and I was told if I really did have low oil pressure my car already would have broken down and I would have noticed it by the way my car drove. I also hit a big rock before my low oil pressure light came on, would that have anything to do with it? I do regular oil changes every 3k miles with Mobile1 5W-30 for high mileage (my beetle is at about 128k). The light still came on after doing an oil change. I don’t know where the sensor would be and if this is a serious problem and if I should be worried or not?

If this is occurring more often, the leak is getting worse. It is important you find this for two reasons. 1) It could be a head gasket leaking, if this gasket continues to fail, you could end up with water getting into the cylinders and/or oil, at which time you will be doing a tear down, and 2) whatever the leak, it it were to fail severely at a high speed, the damage from the overheating may be so extreme before you can get it stopped that the damage will be done, and again you will be doing a tear down or engine replacement. To say nothing of the impending damage to the turbo. Also, if all you are adding each time is water, your system may be full but you will not have running temperature protection from the thinned down mixture.

As regards the oil pressure light issue, slowing on a downhill, is probably sloshing contaminants into the oil pick-up screen for the oil pump, or away from the pick-up. I don't know how it is positioned. Your oil pump may also be bad and be the cause of this. Again this is an issue which needs to be addressed as the Turbo relies on oil for cooling. Also you will greatly enhance cold start oil flow by going to a 0w oil and slightly improve oil pressure with the use of a w40 oil. I suggest Mobil 1 0w40 (VW Certfied).

I have serious doubts the sensors are bad in either one of your issues.

Originally Posted by FootScoot

Coolant temp sensor will set off both lights. On mine the coolant light stayed blue, and the oil pressure light would flash on and off, plus that annoying warning beep. Changed the sensor (1/2 hour job at the most) no more lights.

The oil pressure light snould NOT come on with the low coolant light. The two are serviced by separate sensors. If this happens it could be caused by the oil possibly already breaking down and then under increased temperature thinning even more causing a drop in pressure or by a wiring issue. In your case, fixing the one resolving the other would indicate a false signal being sent to the oil pressure light by the ECM because of the bad coolant level sensor. Strange but possible; under normal circumstances, an indication of low coolant level (with a properly functioning sensor) will not trigger a low oil pressure warning light.

MORAV

[Smileybug]

I have seen a large number of occasions where the coolant light would come on blue, accompanied by the oil pressure light and replacing the CTS fixes both. These CTS failures do some wonky things when they go. My first failure had my car revving up to about 2k or more on startup for about 5 seconds. Replaced the CTS and all was well (I also had a soft code thrown for a cooling system malfunction). Then my second one I had no symptoms. I had no clue it was bad until my cat failed and there was a code for the CTS that was there as well.

[ibbw]

If the blue temp light comes on at start up (as it should)and doesn't go off (when it should) it will begin to flash then in a few minutes the low pressure oil lamp will come on and the alarm will start dinging (usually when the engine rpm drops close to idle) replacing the coolant temp sensor(new green top one) most certainly will fix this problem. I did pull the pan later to check for a blocked pickup screen (was normal) this on a bug just under 100K. I freaked out too at first but I was told had low pressure really occurred, I would know it(engine lock up) I also took the opportunity to put in a new thermostat for good measure. Spent less than 20 bucks and about an hour of my time.

[MacTAC47]

Originally Posted by Smileybug

I would replace the coolant temp sensor. I've read a number of threads where a faulty sensor sets both of the lights off.

I just registered so I could post a thank you on this thread and one other for this fix. I had the problem and it stumped a few mechanics. After reading here (or the other thread) I replaced with the green top coolant temp sensor and it worked like a charm.