|
|
| Head and Head Bolts Removed from Car. Thermostat Housing Still Attached. |
Car: 1991 VW Golf Mk2
Engine: 1272cc
Head Gasket Failure can be a big problem on any car. It's not the damage to the engine that is the problem (if caught early enough!), but the costs of repair, or your own time and effort that is needed.
When a Head Gasket Fails, it can mean water/coolant from the engine getting into the oil, or oil getting into the coolant. If it is beginning to go, you may get some prior warning by additional extra smoke from the exhaust when starting or driving, or less power than usual. Left to continue, either of these problems can go on to cause major engine damage. Of course, sometimes a Head Gasket will go with no prior warning, as in the Rover 800 Coupe found elsewhere in this site!
With this car, the problem was neither of those mentioned, it was the much simpler oil leaking out of the engine from the gasket, so hopefully no cross contamination had happened. This still meant the car would need the Head Gasket replacing though, which did seem like a big undertaking! It is most important to have somebody who understands engines with you before begining a diy project like this!
First we went to Euro Car Parts to order a new head gasket. They offered us a genuine VW gasket for around £65, or, an aftermarket version for around £30. As we only intended to keep the car for a couple more years at most, we opted for the cheaper version.
To remove the cylinder head on any car, always means removing the cam belt too! Removing a cambelt is the most daunting part! This means you have to be sure of what you are doing. So it is most important to follow any workshop manual for the full procedure, for your vehicle, and making sure pulleys are lined up with any Top Dead Center (TDC) markings, and flywheels are held with locking pins etc. when required. (You may also have to rotate the cams from these positions, so always refer to the manual!). Mark the belts and pulleys in a way you can understand later. Taking photos always helps, as with some more complex engines with lots more pulleys, just working out which way the belt fits around them can be a task in itself!
You will also have to remove the inlet manifold and exhaust manifolds from the cylinder head, although sometimes, it may be easier to keep them attached to the cylinder head by disconnecting them elsewhere.
Once you have removed the cam belt, removing the head, is just a question of removing the head bolts from the engine. These will often have torx heads or splined or star heads, so a special tool may be required.
The bolts should be undone in the sequence as describe in your workshop manual, to prevent warping the head.
Then lift off the head, if it's stuck do not try to lever it from the engine block as you may cause damage to the jointing faces, instead tap it free with a rubber mallet. Have some newspaper and/or a bucket ready to put the head onto, to catch any oil that spills or drains from it.
It is important, not to use any sandpaper, or abrasives on any part of the heads or valve surfaces, instead use engine cleaning sprays and a rag to try to remove any deposits or build up that has taken place.
The surfaces must be dry, when refitting the head and gasket, so it is okay to allow it to drain. The gasket should then be place on the engine block, followed by the head. Although this can sometimes prove a little tricky to line up, even with aligning rods, so make sure if you use any sort of masking tape etc. to hold it temporary in place, that you can remove it in full afterwards.
When we first tried to fit this aftermarket head gasket from Euro Car Parts it was obvious that we would have oil problems in future as when we first placed the head on top of the gasket some of the beading was left exposed! So we lifted the head back off, then we applied some head gasket sealant around the gasket on both sides following the beading around the gasket, but diverting the sealant where we needed to. That's what happens sometimes when you opt for the cheaper versions!
The bolts should then be reinserted and progressively tightened in the correct sequence as shown in the vehicles workshop manual. This will normally be from the middle outwards, to compress the gasket/beading equally, preventing any buckling.
New bolts are usually advised, but we just used the old ones, and tightened them all up to the torque required.
Then its just a question of refitting the inlet and exhaust manifolds, thermostat housing, cam/valve covers, replacing any gaskets as necessary. If you buy a head gasket in a set, these gaskets are all normally included in the set.
The difficult part is putting the cam belt back, exactly as you took it off, so as not to disturb the timing, so you must follow the instructions carefully. Don't forget to remove any locking pin from the flywheel.
After this you must remember to refill the oil and coolant levels, before starting the engine! They may also need checking over the following weeks as any trapped air works its way out of the system.
Changing the head gasket on this car, was not too difficult, and we managed to do it in an afternoon.
|
|
|
