Hi all, I am in the very unfortunate situation of coolant getting into the oil of my 2006 SRT. Engine not missing or blowing white smoke. Issues were coolant loss, obviously, and milk-froth oil. Modifications known to me, but before my purchase, were a supercharger pulley and tensioner, and ECU tune. The engine has just ticked over 100,000kms.

The car is with European car mechanics here in New Zealand. The company is well rated, and obviously trusted with expensive and top notch cars judging by the workshop, but it is the first time they have worked on a M112 engine. They are very considerate and good communicators.

There was no external coolant leak. They have replaced o-rings and tested oil cooler. Flushed the engine. Leak remains. They have removed the supercharger to follow possibility of the coolant getting into the engine from the intercooler - which are notorious to fail on the M112. But they say the intercooler is not leaking and couldn't leak into the oil anyway. They are now about to access and check the head gasket. Everyone says the heads never crack on these engines, so I remain hopeful.

I'd appreciate your input on things the mechanic might not be aware of with this engine that they should know - likely causes and fixes.

I'm trying to remain optimistic. Anything fixed now is far less likely to need to be fixed later! I love the car, so I have to pursue the engine fix. While I'm paying for this large piece of work, and assuming the gasket is worth fixing, is there anything else I could be replacing or doing at the same time.

Hey, even some reassurance would be well received right now!

 

Hopefully it may just be a head gasket and not the head itself. If they already have the valve covers removed, you might want to replace those gaskets as well as the RTV silicone gaskets on the small breather covers. They are located on top of the valve covers and tend to leak oil after a while.
I wish you the best of luck.

 

it could be 1 of the o-rings in the front timing cover. we just did an srt6 with the same scenario, email me and i can send pictures rob@needswings.com

 

As far as I know these are ways to for coolant to get into oil. Hope this helps.
Supercharger (SRT only)
oil cooler or oil cooler O-rings (SRT only)
head gasket or head
I recall Nimero has a post talking about 2 gaskets behind the timing belt that can go bad. He had pictures attached.

 

I am able to update on the result here: thanks to Needs Wings my mechanic was able to identify one of the seals for the pipes entering and exiting the plate behind the timing chain. But it still required removing many parts to get to that - finally the sump pan and front block cover.

I instructed the mechanic to replace all the seals and gaskets they came across on the way there.

Fortunately it was not a cracked head gasket, but they were checked anyway. While at it, the exhaust valves were pitted on the seats so they were machined and the heads planed. Valve stem seals were replaced. Planing valves cost NZ$255.

Heads were fitted with new gasket seals and head bolts. Gasket set top NZ$202. Head bolts NZ$241. Head gasket NZ$170.

A new timing chain was fitted. NZ$724 for the chain - most expensive part. There was no clear factory timing info on the engine, and the original crank pulley was replaced. So it had to be marked up again.

Front cover had an entire set of new seals. Air conditioning was recharged - which has sorted the cabin smell and start-up water noise behind the instrument panel air con controls.

Also replaced the drivebelt (aka the serpentine?) NZ$248.

Turned out to need a new battery.

These big part costs, plus small ones and a bunch of labour, bought the cost to 50% of the value of the car. Ouch.

And soon after I got it back I needed a new OEM siren from Needs Wings to replace old one that was randomly going off before I hit my more serious water-in-oil problem. Took the opportunity to replaced RCU with OEM from Needs Wings, which had been resoldered a few months earlier - because I thought I may as well eradicate a future problem. Kept old one as spare. My auto-electrician charged $NZ100 to do both (yes, I could have done the RCU myself...).

 

In my opinion, it may have been expensive for all of that, but it was worth it in the long run. Especially if you're not familiar with working on cars.
In the long run it will be worth it. Now you can enjoy your car and have fun!

 

Thank you - yes, I'm of the same mind. The engine feels completely new - thanks mainly to the timing chain probably - and I feel confident in it. The result is very enjoyable weekend driving.