The exhaust port on my 1985 Passat has a hard white deposit inside it ( I'd post a pic if I knew how!). I thought it might be water but if it is wouldent there be some evidence of failure of the head gasket? There is none that I can see. The valve itself also has some of this white stuff on one side of it so it must be coming from the cylinder somehow. Can anyone help? Many thanks.
Roger
The fuel?
Or any additives in the fuel. I had to take the cyl. head off of an '81 Audi 4000 that was almost completely clogged with white deposits creating a slow rev-ing engine. After the clean up the mileage went past 30 mpg and had plenty of power!! If you don't mind a slow clean up there are chemicals (yep more fuel additives) that should reduce those deposits. SeaFoam (sold in the USA) should be one that can be added to your fuel for a slow clean up. If you don't have a catalytic converter on your '85 you can possibly slowly add it to a vacuum hose that leads to the intake manifold for a fast clean up. Not sure what chemicals are sold locally to you. The fuel?
It is lead from your fuel. No wait a minute, in the USA lead has been banned from fuel for 30 years? In days of old you had to clean or change the spark plugs every 10,000 miles as they would foul up with lead deposits. Now people can get over 100,000 miles on one set of spark plugs. The other replies are probably more helpful.
You are probably right Jim. Since this is a 1985 Passat, those were called Quantum here in the USA! ;-) So this vehicle is not in the USA.
I love logic! lol
Hi Jim. Well until the last couple of fill ups I've been using lead replacement fuel. Now I've swapped to unleaded. If it was the fuel though wouldent it be present in all outlets? Also I've been losing water now for some time very slowly but enough to notice week on week. It continued despite changing the head gasket twice and is the reason I took the head off again so as to get it skimmed. Then I noticed this deposit. Is it linked to the water loss. The head gasket I took off had no sign of failure on the cyclinder in question that I could see. Thanks Jim and to all others for your replies.
Roger
Jim Behn>>The exhaust port on my 1985 Passat has a hard white deposit inside it ( I'd
Hi Dave. Yes you're right. I always forget you're all over the pond mostly.
Roger
dave AKA vwdoc1 wrote:
Some VWs had stretch head bolts. Others had old fashion reuse as many times as you want head bolts. Were you using new head bolts?
Did you have a valve job done so anythng you see on the valves is new stuff?
Did you have the head pressure tested for leaks? Sometimes there can be tiny cracks you may not see that can weep antifreeze.
Do you run antifreeze all the time? Antifreeze is also anticorosion. Over time plain water can cause things to get eaten up. Even with antifreeze I had a huge chunk of head eaten up my Toyota. I had to have the head welded to fill in the missing material and then resurfaced.
A 24 year old car could have antifreeze leaking in many places. I know my Toyota has some annoying leaks. Also running antifreeze lets you smelll leaks. On one of my Rabbits the water outlet off the head was eaten up with corrosion. I had to get a new outlet. Once again antifreeze for smell and visual helps. Bright green is easier to see than pure water.
How are you seeing these deposts? Removing an exhaust manifold is a bit of a pain on the Rabbits (early Golfs), not a task I would be doing regularly.
I would assume that lead substitute is not lead. That whole point of removing the stuff from gas was to get it out of the environment. Not to let some easy to purchase replacement happen.
No the head bolts are the originals. I checked the manual though and no mention is made of changing them for new ones, only to screw them down to a higher torque, and I screwed them down using a torque wrench.
I took the head off and removed the valve gear that's how I noticed the deposit. It's in the head part of the exhaust outlet.
You're right about the reason for dumping lead fuel. Dunno what's in the replacement but it's being phased out. Very few places sell it now. The idea I think was to help out old car owners.
I've never used antifreeze only plain water. I know now was a mistake.
Nope I've never had the head pressure tested and never had the valves out before now.
Thanks again Roger
"Cylinder head bolts with12-point socket-heads are not reusable." Direct quote from the Bentley service manual.
No anti-freeze/anti-corrosi>No the head bolts are the originals. I checked the manual though and no
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.