Q. When replacing a head gasket does the head have to be machined?

**jchamberlain** · 12-11-2008 02:31 PM

I am an 2002 Audi A4 with a leaking head gasket. I am considering doing the job myself and have read a number of DIY posts. The job looks like it is involved, but if I take my time I think I should be able to get through it. I also like the idea of using the kits from ECS so I can address a number of other things at the same time. I went around to local shops to get quotes and was surprised at the differences between cost and hours quoted. One shop always send the head out to a machine shop before re-installing it and that got me to thinking whether that is required or not. None of the posts that I have read suggested getting the head machined when replacing the gasket. Is that normal best practice or overkill?

Thanks,

- James

**lookaught** · 12-11-2008 02:54 PM

I would machine it ONLY if it is warped. Gaskets are cheap, and you'll learn a lot about your car if you DIY. So DIY, and hope that just the gasket will fix the problem. If it doesnt then go down the machining road.

The simplest solution is usually correct. I live by those words.

**fitch303** · 12-11-2008 03:56 PM

Machining is cheap anyway.

**dirtybrd** · 12-11-2008 03:58 PM

Check it to make sure it's within spec. If it's good, then go ahead, if not machine then install.

**BARRY** · 12-11-2008 04:59 PM

check the head for trueness with a metal straight edge ruler. or a dial indicator if you're fancy.

you don't necessarily need to, but for a boosted engine i would plan to resurface the head at all times the head is removed.

**absolutegtr** · 12-11-2008 05:04 PM

When a headgasket goes bad, you lose coolant...so if the car ever overheated I would definitely send it out to be checked for warpage

**Audi Skate Snow** · 12-11-2008 05:05 PM

no need to send it out.... get a straight edge (not any straight edge though) and feeler gauges and check for warping. there are about 6 measurements. 3 diganal each way corner to corner, then other corner to corner

**dirtybrd** · 12-11-2008 05:07 PM

I had 90k on my head and didn't resurface it. As a matter of fact, I didn't even replace the valve seals. I've run a 3071 @ ~25psi on a fully built motor for over a year and have 1 of only 2 B6 2.0's that haven't had to come apart again on here. Call me crazy or maybe I know a thing or two. I have to give Dougyfresh his props!

**jchamberlain** · 12-11-2008 06:09 PM

Thanks so much for the information! If I take it off I will definitely measure it to make sure it is not warped. First I'll have to figure out the right way to measure it, are there tolerances that are considered still within spec or if it is not perfect then it needs to be milled? If there are tolerances are they called out in the Bentley manual. I haven't bought the manual yet, but I plan to. I believe the head gasket leak was fairly minor, it would slowly leak coolant causing it to need to be topped off maybe every couple weeks. Then after a while like that it started to progress to the point where it reduced greatly on my way home from work one day. I have never seen the temp gauge go high or elevated at all and the engine is completely stock. I have not driven it since that day.