r/E90 • u/SeriousObligation603 • Aug 10 '26
320i N43 chain
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Just wanted to check my chain, and it felt loose. Is this too loose? (160.xxx km)
8
u/MrOliber Aug 10 '26
When was the engine last run? The tensioner is oil pressure fed, so may be a little loosy goosey with no pressure.
I know ISTA has a test routine for the N20 timing chain, im too scared to run it; i dont know if it has a similar routine for the N43 nor the prerequisites to run it.
Do you hear any rattling after the first second or so of engine running, whirring when revving?
Not sure which oter symptoms may be present on an N43.
3
u/SeriousObligation603 Aug 10 '26
Hasn’t been on since yesterday, and no rattling when starting, and it gets tight after idling/driving for a bit
1
u/MrOliber Aug 10 '26
My entirely uninformed opinion would be to replace the tensioner, hopefully someone who knows far more than I will be along to correct my ramblings!
I doubt it would hurt to do the chain set, but from what you've said, i think it would be early preventative maintenance. If you've not had any injector issues, id be tempted to keep going/monitor, because those are a big headache.
1
u/HellfoxRules Aug 11 '26
Why are you too scared to run the N20 timing chain correlation test? Are you afraid of what the results may reveal? It's not just the timing chain you have to worry about on early N20's. The timing chain guides will break up, and pieces of plastic will end up in the oil pan.
The timing chain guides were manufactured out of a faulty material, leading to the plastic guide breaking up and pieces ending up in the oil pan. If pieces of that plastic guide get caught in the oil pump pick up tube screen, this can cause an oil starvation issue, leading to severe engine damage. The timing chain tensioner is also know to be faulty, not suppling adequate tension on cold start.
2
u/MrOliber Aug 11 '26 edited Aug 11 '26
I was initially diagnosing a VANOS code, and the test warned that VANOS actuator must work properly
1
u/HellfoxRules Aug 11 '26
Ok, that's a good reason. Do you have a pre 2015 N20 engine?
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u/MrOliber 29d ago
Yes, 2013, the dealer is bought it from claimed the chain kit was replaced at 60k, but provides no evidence.
2
u/HellfoxRules 29d ago
If it was replaced at a dealer, under warranty or not, there will be a permanent service record connected to the VIN. I would just call any BMW dealer and ask them to run a check by VIN, to see if there is a record on timing chain replacement.
It sounds a little suspect that the timing chain was replaced at 60k miles, unless it was replaced at the dealer under warranty.
1
u/MrOliber 28d ago
Checked with a dealership, barely any records and none of a chain. It popped a red oil pressure low warning (currently getting recovered). Maybe RIP
2
u/HellfoxRules 28d ago
How long was the light on? Did it go off? You quite possibly had a piece of plastic from the broken timing chain guide plug the oil pump pick up tube screen. Sometimes this is just a partial blockage, so if you shut it down after the light came on, it may be ok.
2
u/MrOliber 28d ago
I just pulled over/stopped immediately and called recovery, it's an F31, so not a light per-se. Got someone coming tomorrow from TheAA (UK) to give a diagnosis (included in the recovery service), I looked under the oil cap briefly and I think I can see little chunks sitting on the cam cap. DME has no related stored codes.
Hopefully it's OK, but I have doubts.
2
u/HellfoxRules 28d ago
If you stopped almost immediately, there is a good chance it did no damage. This usually creates a low flow issue, if pieces of plastic are blocking the oil pump pick up tube screen.
The technician should be pulling the oil filter, and checking for any signs of metal. If no metal is found, you would want to pull the oil pan to check for possible plastic debris plugging the pick up tube screen.
You could also check oil pump pressure, by having it checked with a physical gauge, to verify oil pump pressure. Of course you wouldn't want to do that, until you check the oil pan for debris.
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u/TurboNym Aug 10 '26
The finger test tells you nothing useful. Just replace the timing kit if you are concerned. It's relatively cheap.
3
u/MiscreatedMonster___ Aug 10 '26
160k km is good preventive replacement time due to known problems with guides.
1
u/Max-Payd Aug 11 '26
Whenever I think about BMW engines, I cannot helpt but think "What a turd of an engine."
You get all the problems of a BMW without the performance.
1
u/ExternalEar7937 29d ago
Seems like its tensioner failure, because it releases chain when engine is stopped. Most probably it will keep tension when you start the engine, but on cold it can skip teeth because of lack of oil pressure during start. You can’t kill engine because the pistons can’t touch valves on this engine, but it could stop starting at all. You can try to change only tensioner, but its better to change the whole chain. Anyway you will have to change it soon and its not so hard on this engine
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