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Discussion Starter · #1 ·
Hi Everyone :wrench:.

Just bought a 1998 1.8 T 5 speed manual with 140K miles. The only thing the seller knew about it was it had a new clutch put in at 120K miles and the oil was changed at Jiffy Lube. :hmmm: Very clean original condition inside and out. Has all the original emergency kit, spare tyre, tool kit and even the original floor mats. It had not been driven in months. It started right up when I went to look at it. The test drive was around the block as the temperature gauge was not working. The drive home was about 8 miles. The temperature sensor was installed yesterday which gave me the vitals to take it for a good drive. I have an engine knock. :banghead:

Well here's the symptoms. It knocks for a second when cold starting till oil pressure builds. It remains quiet when cold no matter what you do. When it reaches operating temperature it doesn't make any noise till I reach about 4000 RPM or when there is no load in gear going down the highway. There is no knock at any time when idling. There is knock at 2000 RPM and higher in the garage. Pulled the tupperware off yesterday and it has leaks on the bottom end of the block only. Top end is clean. The power is equivalent to a 60's single port 1200 cc beetle. :mad: I have purchased new seals and gaskets for it (excluding rear main, head gasket and sump pan). New turbo as I read that these have a tendency to fail at the wastegate. New belts all round with tensioners.

I am assuming the worst case which is rod bearing gone bad. Unless someone with a little more experience with these engines can tell me otherwise.
 

· PassatWorld Elder
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I would start with an oil pressure test and then pull the valve cover and a couple of cam bearing caps to check for damage. The bottom ends are usually robust, so a rod knock is probably from a low oil pressure issue. If there was a low oil pressure issue, the 1st place to look is at the cam bearing caps. It's also likely the turbo has seized from a a lack of oil pressure.

After that, decide if a replacement engine is cheaper than rebuilding (depending on the damage found).
 

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Discussion Starter · #3 ·
Thanks for the reply.

Today I read the post and removed the rocker cover. Sorry I never replied but my hands were filthy. I removed one of the bearing caps on the cam and it is clean and serviceable.

So I pulled the cars face off completely. I did find a new cam belt and peripherals so someone has done some maintenance to it as I can still read the insignia on the belt. The turbo turns freely with no end play at all. It is the original as the cast has a 98 stamp on it. Unless they replaced the core. I did find a lot of oil in the intercooler passages and in the intercooler itself. Cannot understand why there is no power. Turbo next to see if the wastegate is open.

I guess I will keep pounding away at this until I find the problem. I know about the mission involved in removing the sump and I am not looking forward to it but I have no choice now.

To infinity and beyond!
 

· PassatWorld Elder
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Since the front is off, check the inside of the turbo, look to see if the blades made contact with the sides. I removed one dead turbo that would spin by hand, but did not produce any boost and the fins had scraped the side when under throttle. Also check that the DV is working properly as that will also limit boost.
 

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Discussion Starter · #9 · (Edited)
Thanks

I did remove the turbo last night and the waste gate was open. Well it was loose and I could fit a matchstick past it. The turbines are not damaged in any way so I think I may keep this one to rebuild at some point. I have a new one here non OEM. Anyone had some experience at the $150 turbo's on eBay?

Also, I have done the "wooden dowel test" buy pushing on all the pistons on the down stroke to look for play on the rods and I have nothing. I repeated the tests numerous times and there is no play. I am at a crossroads now as reassembly with all the new parts is next. I really don't want to pick the engine if not necessary. It has been a major PIA so far. Never knew these little engines could get so complicated. Anyone that could think of what else this could be? The dual overhead valve train I have no experience with. Tensioner on the cam chain, sticky lifters maybe?

Guess I checked the wrong PVC Valve. I will order one of those now.
 

· PassatWorld Elder
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A sticky lifter is possible, but once it is back together, check the oil pressure. Then use a mechanic's stethoscope to narrow down the knock. The Ebay turbo may last a month or a year, you never know. A used one might be a better choice.
 

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Discussion Starter · #11 ·
Agreed.

I guess I will be starting a good old survey on this turbo.
Its pretty much back together now. Have a question, I heard another knocking noise that I have never heard before. Scared me so much that I shut it down. Started it back up again and tried to find the source of the noise, it is LOUD and it came from this part in the picture. Is this a vacuum pump of some sort? It makes a knocking noise intermittently then stops. :crazy:

Auto part Fuel line Engine Vehicle Automotive fuel system

Also do I need to bleed the coolant?
 

· PassatWorld Elder
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That is the EVAP purge valve, a vent for the charcoal filter. It should click, not knock.

You will need to bleed the coolant after a turbo change.
 

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Discussion Starter · #13 ·
PZ

I want to thank you for all your help. :thumbup:
Don't know what happened to the "rod knock". It's just gone. :confused:
I need some rest now. :sleep:

Its a screamer. My son's going to love it! :driving:
 

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Discussion Starter · #14 ·
That is the EVAP purge valve, a vent for the charcoal filter. It should click, not knock.
This car is running great. We did 190 miles today and it cruses real well.
That purge valve is awful. It sounds like a woodpecker making a new home out of the air box when I stop at a light. Do you think that its a sign of a bad charcoal filter. I also noticed it will not fill when you use the stop on the handle at the gas pump. It takes a hand to fill it so I am guessing a new charcoal canister? It that why its clicking like that?
 

· PassatWorld Elder
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I've never heard a loud purge valve, usually they just stop clicking. I am not certain if the purge valve is the same as the tank vent valve, but I have seen the tank vent valve blamed when cars keep shutting the pump off when fueling.
 
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