Help! I recently got problem with the engine in my VW Passat 1999.?

Question

After a short trip of 70 miles it began knocking. At least, it sounds like. Along with that the coolant is leaking. Every time Overheating/Low coolant lamp is blinking, you can't really say what is wrong, because the engine is really hot, and there is no water in cooling system. I am worried about the engine. In a day I am taking the car to mechanics, but want to be a little prepared, otherwise, I will be fooled. It happens so often in SF City, CA. Can you tell me how bad the problem sounds like, and what it might be. Thank you

Answer 1

It could be a possiblity of a number of things. Being you said that the engine sounded like it was knocking, then I would have to say it might be serious.

I would guess that a head gasket or cracked head could be a possiblity. Also a defective water pump could create the same problems and make the car sound like it's knocking.

Being the car is a '99, the warranty might cover the cost of replacement and labor (assuming the car was bought new and you are the first owner).

Expect any work done to be a bit expensive being most parts have to be shipped in from overseas (depending on the dealer).

Answer 2

You obviously have a coolant leak and they will start with a visual inspection of the water pump, hoses, radiator, and the head gasket and possibly the heater core. Once they identify the leak they will give you and estimate on the repairs.

The problem that can follow an over heated engine is that the cylinder head can warp a fraction of a millimeter and if it is not already leaking from the headgasket it can show up later.

The knocking noise could be from coolant getting into a cylinder and you are hearing the piston trying to compress the coolant which it is not designed to do and can damaged the cylinder head, piston, connecting rod, and rod bearings and the crankshaft.

Worse case scenario is an engine replacement (you can get a rebuilt motor with a decent warranty) or you might get lucky and just need a hose replaced and or water pump.

The problem with low coolant is that there will be no coolant flowing though the cylinder head(s) and eventually the engine block if the leak is bad enough. So, then there is no coolant to carry away the heat during combustion and send it to the radiator to cool it and circulate it back into the motor.

Plan for the worst but hope for the best.

Good Luck!

Answer 3

It does sound like the thermostat is stuck closed; if the engine had a knocking noise that isn't good! Its a sign of severe overheating that can be caused by oil failure due to high temperatures. Spark knock could also be caused by overheating the engine. The coolant loss is significant; where is the coolant leaking from? The engine/water pump? A hose? The radiator? I'm retired from spending nearly 30 years in the automotive service business, 25 years on and off with VW dealerships, last in a VW dealership in December 2005. Let the engine cool before restarting and checking the coolant level or adding any... I'm in the SF area; I could take a 10 minute look at it for you, I won't work on it, but if you're in SF during the day, perhaps I can offer an outside opinion.

A car nut.

Answer 4

well the knockin noise is a valve knocking but its usually a pretty easy fix for anyone who knows about cars the overheating could be anything from a bad thermostat around $10 or a water pump its most likely the thermostat

good luck

Answer 5

Sounds like the thermostat is not opening. It the top hose that goes from the radiator to the engine block. At the block under that hose is the thermostat.

Answer 6

=)