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amdaman

E39 Coolant Leak after pipe change

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Hi, 

I had to change the coolant pipes under the intake recently on my 530i because they had started to leak at where the pipes entered the block. When I removed them the plastic had fused to the block as the pipe was removed so I had to scrape away all the plastic and mangled orings for quite some time. 

Anyway the new pipes came and fitted, topped up and ran using the bleed screws initially. Went on a drive and the heaters started to get warm again which was great. Got back and it starts p155ing fluid from the hose connected to the thermostat housing! Even after I turned off it was hissing and spraying water in that area! 

What have I done wrong? The only thing I can think off is I didn't get all the old plastic out of the housing so the orings aren't sealing? A friend has suggested an airlock and will bring his pressure tester up.

I'm trying to keep it from the scrapyard as I like driving it but it's testing me.. Is there anything else I can try before I take the manifold off? I'm trying to avoid that if possible as it wasn't the most fun job (especially those injector clips). 

Thanks 

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Are you talking about plastic pipe you replaced or the actual rubber hose going to thermostat? You need to clean with wire brush etc and lube those orings when installing those pipes and usually orings on hoses to reduce risk of damage

There are 2 bleed screws. I blow into the expansion tank with thermostat one cracked to push air out before starting the engine, then repeat with expansion tank one, speed up process if you don't have pressure tester etc

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Hi - the plastic pipes that go into the block that sit under the intake manifold.  I lubed the o-rings up to get them in the housing..  I did think about the wire brush but getting it in seemed like a struggle.  I used a pick and mini scraper and it took a while.  I think I slipped a disc too (lol) .. I'll see what the pressure test says then, will I have to buy some new o-rings if I'm going to do this job again?  Will the intake manifold and throttle body gaskets be ok too?  They were all new.

Thanks

 

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Yeah i use a small wire brush, fine sand paper, brake cleaner and a rag to make sure its mint. If it has corrosion then i use a small amount of sealant wiped around to fill in the imperfections.

Was it the genuine part? i know some aftermarket pipes can have problems seating correctly due to tolerances.

I wouldnt risk re-using the o-ring again given what the job like, but if you have access to pressure tester then you can test it properly before putting the intake on if it needs to be re done. Throttle body and intake gaskets should be ok to reuse given they are new.

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I was going to ask about the sealant, this is what I was going to try after cleaning it. It was aftermarket from Pelican Parts so maybe that explains it although the pipe was very hard to get in, I had to put a dab of wd40 on the orings to get it in.

I'll get some more orings from Winger then. I've just started taking the car apart when I got in today after work and the manifold is almost off after 45 mins.. So much easier when you've done it before.. The injector clips came off so much easier as well. I'll do the rest on the weekend. 

Cheers

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I definitely wouldn't be using WD40 for something like this, for example you can get a silicone grease from Repco that would be a far better job for sealing and lubrication while costing very little

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So I took the pipe off again this morning and one oring was snapped and the other was a wierd shape. No idea how or why. The other pipe was fine. 

So the oring spec appears to be 20x3mm, can I just pop down to repco and get these or do I have to get them from BMW? 

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From what you say it's most likely seated incorrectly due to inadequate lubrication of o-rings and\or the surface not being prepared properly (smooth to touch). I did my own car yesterday and used a small wire brush then green scotch bite to clean and a flush to finish. Used a coating of tap grease (in my case) on both o-rings and holes to prevent any damage upon install and make it easier to fit.

I doubt Repco would have anything. I use seal innovations for most of my o-rings but you could try the dealer.

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Thanks for your help, I got a wire brush in there from a Dremel today. Supercheap had a multi pack of o rings and one size was 20x3.5mm which was a nice snug fit. The difference was I put some rubber grease on this time. The thing is sealing now. I've missed driving it. The R8 can stay in the garage! Thanks again. 

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