Oil Consumption: 2L/100km After Timing Belt & Head Replacement

Hello everyone,

I am the (un)fortunate owner of a 1/3 share of a LT28 from 1990 with a 2.4L pre-chamber diesel engine and 57 kW. One of the other co-owners caused a timing belt failure just before our planned vacation. The camshaft was broken in four places. An inspection of the belt revealed that it was definitely due for replacement. However, all the valves still looked good. Nevertheless, we installed a new cylinder head (from eBay) and went on vacation. The seller claimed the head had been refurbished.
After the first 1200 km, the oil light came on. To our great surprise, we added oil and created a reserve. During the next 4000 km, the oil consumption settled at 2 liters per 100 km. Helplessness...
During the inspection while the vehicle was on tour, no significant oil leaks were found. However, a large amount of oil mist was visibly escaping from the crankshaft seal, and oil was seeping out from under the timing belt cover. Anything that couldn't accumulate there was being forced into the engine compartment and leaking out. The LT is now removed and effectively protected against corrosion at the rear .
In addition to the excessive blue-gray smoke it was emitting, the car was burning so much oil that we had to accelerate and rev the engine to prevent the exhaust fumes from knocking out any following drivers.
My suspicion was that the eBay seller was trying to trick us and had completely omitted the valve stem seals .
After 6000 km, the car suddenly started having trouble starting properly and soon needed to be pushed to get it going. The fact that it would eventually start when pushed led me to suspect compression problems. I did some brainstorming and suspected carbon buildup on the valve seats. However, I just read a short comment here about high oil consumption and damaged piston rings after a timing belt failure.

Now, the big question: Can the impact of the pistons on the valves cause damage to the pistons and cylinder walls that would result in such high oil consumption? (The pistons and cylinder bores showed no visible signs of damage.)

By the way, after the entire trip (9000 km), we had consumed almost 200 liters of oil through the engine and exhaust systems of those poor vehicles.
We haven't figured it out yet, but we know we need to. If you could give me any clues about characteristic features that might indicate where the oil has thinned, I would be very grateful.

Best regards, T3.

Hi,
If air is leaking through the crankshaft seal in this way, it suggests that there is excessive pressure in the crankcase, which could be caused by damaged piston rings and/or worn cylinder bores.
There would be quite a strong gust of wind if you unscrew the oil filler cap while the engine is running.

Hello,

A quick compression test of the cylinders would provide clarity regarding worn piston rings or damage to the cylinder bore surfaces. Don't forget to also perform a pressure test of the crankcase.

'I'm sorry, but where exactly did you end up going?'
9000 km and 200 liters of oil???

I don't understand that at all!

Especially outside of Germany, mechanics are very familiar with older cars and will repair them for a small price.

During my vacation in Italy, I had to drive slowly for 40 kilometers behind a Peugeot that was likely experiencing a similar minor oil issue.
Even on my paint, there were oil stains everywhere!
And we shouldn't even talk about the pollen filter; it probably smelled terrible!

When the traffic came to a standstill, I tried to talk to him about it, but we didn't get very far due to my lack of Italian.
But as far as I could understand, he was on his way to the workshop!
And he let me go ahead! *What luck!*

Hello.

Did you also replace the pistons? Probably not. It's not always necessary after all.
A timing belt failure. These inline-five engines are extremely prone to timing belt breakage. There aren't many ways for the engine to consume oil (not leak it!). It's either the pistons or the valve stems. I suspect the latter.
Okay, then there's only one thing to do: remove the cylinder head and check (the valve seats/stems).
and if necessary, overtake.

Good luck.

Hello,
It's quite possible that the piston rings are no longer moving freely, and the lack of pressure prevents a proper seal. I've seen this before with a 1.6 TD engine where, after a timing belt failure, only a new timing belt was installed, and everything seemed normal until, after over 100,000 km, one cylinder lost compression. When disassembled, it revealed pistons with stuck rings that had been forced against the valves. New pistons were then installed, and the engine is still running today.

Andreas.

Dan.jel wrote:

Sorry, but where exactly did you go? 9000 km and 200 liters of oil??? I don't understand that at all! Especially outside of Germany, mechanics are very familiar with older cars and will repair them for a small price. Even on my paint, there were oil stains everywhere!!!

That's true. It's a bit antisocial!
"When someone drives in front of me like that, I wish I had a black magic kit."

I also had that problem with the oil.

Timing belt failure at 120,000 km (approximately 75,000 miles).

You probably won't have any other choice but to disassemble the engine again!

In my case, the oil scraper ring has almost completely worn out. *g*

When the valves open, vibrations are generated in the piston, similar to striking an anvil with a hammer. These vibrations cause the oil film of the lowermost ring on the piston to be disrupted because the shaft vibrates most strongly at that moment. This results in extremely high wear on the oil scraper ring.

'In my engine, only the oil seals were worn; both sets of piston rings were like new.'
I also had an elevated blow-by value, and I still don't know why. *g*

200 liters of oil according to the standard easily costs between €1000 and €1400!

For that amount of money, you could have easily had the engine repaired.

Regards,

Manuel.

Thank you.

To those who have answered me objectively, I appreciate it. It seems like I will probably have a lot to do.

And now, for the know-it-alls. I actually didn't want to say anything about this, but before this thread becomes more focused on my supposed 'antisocial behavior' than on the actual problem, I feel like I should briefly explain myself.
'200 liters of mineral oil costs about 200 euros - this cheap oil is perfectly sufficient for the engine. In fact, you could have bought another cylinder head with that money (on eBay). But it seems like that wouldn't be enough to fix the problem. If I had gotten it repaired somewhere in Western Europe (where we were traveling), I would have had to leave the vehicle at the workshop and hitchhike home. Contrary to what some people seem to believe, goods are not accepted as payment anywhere outside of Germany. And if I could afford a repair for 1400 euros (which wouldn't even be enough), I wouldn't own 1/3 of an LT28 from 1990, but rather a Sprinter.'
As mentioned earlier, our car mainly burned oil. While the car was indeed oily, this was after it had been driven for 9,000 km. Those who drove a few kilometers behind us – which was rare given our speed – therefore didn't see any oil droplets on the paintwork, but rather just a little passive smoke.
I don't want to downplay this. I also know that if everyone did this, 'If Everyone Did That' would soon have to reintroduce smog levels, but I only do things like this when there's no other option. I'd be interested to see the person who cancels a long-planned trip because of something like this.

Best regards, T3.

I still think it's pretty ridiculous to drive that kind of car on vacation.

If it needs that much oil, it could suddenly seize up, explode, or something else bad could happen. And then you'd be stranded out in the wilderness with everything and everyone.

Okay, great...

If the piston rings are stuck because the valves have been damaged, the damage to the ring area or the crack in the piston won't be extensive. And not every engine will continue running with a broken connecting rod and one less cylinder. If you're unlucky, the engine block now has significant scoring and needs to be reworked.


CU Gremlin.

if, for example, it has stuck piston rings because the valves have been damaged, the seizure will be in the ring area, or the crack in the piston won't be extensive... and not every engine continues to run with a broken connecting rod and one cylinder less... if you're unlucky, the block now has beautiful scratch marks and needs to be reworked.

You're probably right, but I didn't know at the time that it could be related to a piston – this thread just brought that realization to light.

Best regards, T3.

Thank you for the flowers!
You probably have no idea how quickly you can be overtaken when riding in the back.
I don't know if that oil mist is harmful to your health, but it definitely smells awful!

And if we're talking about being condescending: You should divide the potential repair costs by three before lecturing us about how expensive it is for you.

Furthermore, one can find a justification, often referred to as an excuse, for anything.

T3-TDI-Sporter wrote:

Thank you, I'd like to meet the person who just gives up on a long-planned trip for some reason. Regards, T3

For example, me.

I once replaced a head gasket and soldered a radiator on a highway rest stop. That was enough for me.
"With an LT28, you're pretty much stuck if something suddenly pops out of the engine block. I would have taken the engine back home and resealed it, even if it cost me two vacation days. The return trip for the family by train and potential customs fees for bringing the damaged vehicle abroad are always more expensive."

Best regards,
Christian.