Bent valve not caused by bad timing?

This forum is for TDI (Turbo Direct Injection) questions/posts. Non-TDI Motors (Including the 1.6, and 1.9 or other variant turbo diesel motors) should go in the VW Diesel General Forum

Moderator: Fatmobile

Post Reply
Cetane Booster
Posts: 31
Joined: Sun Jan 30, 2005 5:01 pm
Location: Glassboro Nj

Bent valve not caused by bad timing?

Post by Ottman »

I found a TDI for sale and it says it had bent valve due to the waterpump and the timing belt is not broke.

I was wondering what kind of damage is caused by this and what might possibly need to be replace, Thanks in advance.
Turbo Charger
Posts: 791
Joined: Mon Oct 17, 2005 7:21 pm
Location: Kansas City area, Missouri

Post by CoolAirVw »

Sounds like non-sense to me. But hey if the car is cheap buy it! Note sometimes the head breaks and you cant just replace some valves and do a valve job.


OMG was that too blunt? :)
85 Jetta TD
ASE Certified Master Auto-Technician with L1 Advanced Engine Diagnostic Rating and Light Diesel certification
ATRA Certified in Rebuilding, Diagnosing & Installing Transmissions

My Threads---> <a href="viewtopic.php?t=6255&postdays=0&postorder=asc&start=0" target="_blank">Rusty Floor Repair </a> ---- <a href="viewtopic.php?t=4923&highlight=" target="_blank">Oil Pressure Warning</a>----<a href="viewtopic.php?t=6632" target="_blank">Uploading Pictures</a>----<a href=" ... t&p=730755" target="_blank">My Porsche 914</a>
Diesel Freak
Posts: 109
Joined: Wed Dec 18, 2002 4:55 pm
Location: Western MA

Post by MayorDJQ »

I can't think of how the water pump would ever affect the valves. Maybe a blown head gasket would allow a cylinder to fill with coolant, causing hydrolock and a bent rod, but that's pretty serious.

The seller may not know what's actually wrong with the car. Presumably a valve gets bent by getting hit by the piston. If that happens, the vale seat, valve guide, spring, and possibly the cam lobe can be damaged.

You might want to stay away from this car.
Turbo Charger
Posts: 222
Joined: Sat Oct 01, 2011 10:38 am
Location: North Dakota

Re: Bent valve not caused by bad timing?

Post by texcl »

A seized water pump can cause the belt to skip teeth and go out of time causing puston to valve contact.
1980 Dasher 1.5l
Redneck truck
Glow Plug
Posts: 9
Joined: Thu Oct 18, 2012 8:59 pm
Location: Dallas, TX

Re: Bent valve not caused by bad timing?

Post by Redneck truck »

Definitely nonsense. Warped head from water pump, maybe. Bent valves from timing almost exclusively, single bent valve from some combination of incorrect timing, valve float, or bad guide (prior rebuild)?

Depending on the model, a single valve failure can warrant a total engine rebuild - the head breaks off, breaks apart, and makes its way into all other cylinders via the intake or exhaust manifold. Rods get bent, and of course, at least the offending piston and corresponding combustion chamber require major repair or replacement.

You can find a running one cheap enough; I wouldn't pay more than $1,000 for this car, and that's if it's clean.
air-cooled or diesel
Turbo Charger
Posts: 281
Joined: Fri Jul 15, 2011 7:03 pm

Re: Bent valve not caused by bad timing?

Post by air-cooled or diesel »

some tdi's had the water pump driven by the timing belt, this will be the same issue as a bad/broken timing belt. you may need to replace valves and valve job, you wont know the full damage until you pull the head and see if the pistons are intact. if all are ok you should be ok with new valves, a new head in the extreme. check cam, may have taken a hit from a piston coming up into a valve, in which case you need a cam. you may need lifters too (if cam is ok, if not new lifters too). i've blown a couple of valves over the years and ended up with no/or almost no piston/lower engine damage. if you have a hole in a piston, then you've got real problems. like oil carrying engine parts thru the motor. but doesnt necessarily have to be the case.
Post Reply