Hi, I'm a 23 yr old girl who just bought a 1993 vw cabriolet with 170,000 miles on it and I've had numerous problems that seem to be neverending. The problem today was that the engine overheated and at the same time, the oil warning light came on. When I opened the hood, I saw a liquid bubbling on the engine right around some sort of pump. The gas station attendent told me that the liquid was oil and the i'd probably need a new headgasket. When this happened, i'd been driving on the highway for about 20 minutes in 90+ degree weather, and then on side roads for about 10 minutes. So we put some oil in the car and put water on the radiator, and since then (that was this afternoon) its been running fine. When I first bought the car, which was about 3 weeks ago, it had been sitting in the owner's driveway for over a year. I went to drive it home and it didn't make it more than a mile without overheating. The mechanic said that there was a problem with the fan, so he rigged it so that the fan now runs at all times. Then when I went to go pick it up again, I put some gas in it and then it wouldn't start. The mechanic looked at it again, and when he did, it just started running without him fixing anything. Then I took it to another mechanic to get it inspected and he told me I would need an alternator, a coolant switch, a coolant leak fixed, some spark plugs, and an exhaust leak fixed. So I got the coolant leak and the spark plugs done because that was all I could afford, and he said that's what I needed the most. Then when I picked it up today, it started with all the problems I wrote of in the beginning. I called him and he said that maybe the noise he heard that he thought was the alternator was really the water pump. Most people are telling me I need a new head gasket. But there was no white smoke coming out of the exhaust, and the coolant didn't seem to look weird, but I don't know that much about cars. The only thing that was really noticeable was the oil bubbling on the front left of the engine, right where a tube was, and the oil light which went on at the same time as the temperature warning light. It's been driving fine tonight when the weather was not as hot, and I did add oil and put water on the radiator again. I just don't know what to do. Some people are telling me to just get a whole new engine. Some people are telling me about sludge, and others are talking about filters of some sort. I'm so confused, I already spent $500 on repairs and I just don't know who to believe at this point. I'd really really really appreciate your advice - thanks!
Let's tackle things one at a time. Golfs/Cabriolets can actually be fun to work on. I'd suggest getting a repair manual put out by Bentley Publishers. Used is the best way to go on these, as last time I bought one it was $60 new.
There is a thermoswitch that controls the fan. (A switch that turns on at a certain temperature.) It would be worth going back to that setup, rather than having the fan on at all times, especially if you live somewhere that gets cold in the winter months.
As for the waterpump, it can cause overheating if it is not working. A stuck thermostat can also cause overheating. It's always worth trying the thermostat first, as it only costs about $5-$10 at a parts store.
If you needed a new head gasket it would be pretty apparent. You would have visible steam coming from under the hood and from your exhaust. You would see water in your oil most of the time too.
The hose where the oil is bubbling sounds like it may be a PCV valve or filter. ( PCV is Positive Crankcase Ventilation) this hose serves the purpose of allowing heated air from the engine to escape, helping to prevent your oil from getting frothy. If the filter on the PCV valve is clogged, it may be preventing the vapors from escaping through it, and they are going around it instead.