[Jaminlow]

Hi all,

I have a 325i N53 which is unfortunately experiencing an internal coolant leak into cylinder 2, this has been diagnosed a possible warped or cracked head.

I would like to know if anyone has any experience with reconditioning an N53 engine or if anyone can recommend a decent company that might take on this kind of work?

I've had a lot of quotes from companies claiming they can do a full refurbishment ranging from £2700 - £4000 with 6 -12 month gurentees and I'm trying to decide if reconditioning is worth it or if it would be better just to swap out the engine for low milage used one.

Any input would be much appreciated

[Phil325i]

Sorry can't recommend anyone for the rebuild. However, I would recommend getting a second opinion on the root cause. Yours will be the first N53 I've ever heard of having a warped or cracked head. The basic mechanicals of these engines are pretty bulletproof. It's the peripherals that give problems (HPFP, injectors, coils etc). Unless you know the probable cause of your coolant issue, I would get an experienced BMW specialist to double check whether that is in fact what the problem is. Just a suggestion...

[Dormermike]

+1 to wot Phil said. You want to be 100% on the diagnosis. Make sure it's not the coolant/oil heat exchanger for example.

If it is a head gasket, it's not actually too bad a job on these even if your head needs slimming. Id rebuild or at least whip off the head and get it checked and pressure tested. But, it won't be a cracked head.

[Jaminlow]

Thanks for the reply's guys,

Agreed, I've had two BMW specialists take a look at it and they've both determined that coolant is getting into cylinder 2, I actually ended up taking the car to A1 German car specialist for a 2nd opinion, I believe they were recommended by Phil and seem to be very professinal, they even sent me a video from scoping the bores which clearly shows liquid entering the cylinder 2 all other cylinders are unaffected.

Im tempted to get the block checked out but my only concern is if it this has happened due to overheating or some other malfunction the rest of the engine is likely damaged and il have to spend the best part of a £1000 just to find out I need a full rebuild or new engine, everyone I've spoken to seems to say the HG is bulletproof and very unlikely to leak so definitely a dilemma

Most rebuilds seem to be in the area of £3500 and Im very skeptical about the quality and longevity of the rebuilt engine, for this price i could probably fit a used 330I engine with a 330i map and get some more power out of it.

Il definitely looks into the coolant / oil heat exchanger, do you think this would result in coolant getting into the cylinder?

[SRLA]

A heat exchanger failure would cause coolant to get into your oil or vice versa but not a leak into any particular cylinder.

If your engine overheated and that damaged the head gasked or warped the head that probably wouldn't have damaged the block itself and you shouldn't need a rebuild. An oil test for metals would show if you had any issue with your main bearings for example to give you peace of mind.

Take the head off to see what's really causing it. If it's just the head and/or gasket it's not too bad, new gasket and skim the head and you're good to go. In the unlikely event there's block damage I think I'd skip the engine rebuild/swap and just look for another car. N53 325i's can be found from around 4k nowadays and you could sell that off to get some of the money back, it'll work out cheaper than the repair.