Major Coolant leak even after Head gasket job!!!

[Big Red]

A few months ago I was driving down the freeway and when I exited I noticed that the engine was running a little funny, I pulled over popped the hood and steam was coming from everywhere, frothy brown stuff on the dipstick led me to believe it was a blown head gasket as there was obviously coolant in the oil.

I had the car towed home as the engine was still able to run and I wanted to salvage what I could and maybe even get the car running again.

Fast forward a couple of months, I had the head resurfaced and had a valve grind job done at the same time, following is a list of thing’s I did and stuff I replaced:

The cylinder block was flat, the head was warped, there was no obvious breach in the head gasket.

Head resurfacedValve grindNew head gasketAll new gaskets from the head upThermostatWater pumpFuel filterSpark plugsDrain & refill oil and coolant

I get the car back together again, fired her up (see note) and it sounded like a diesel bus, I let it run for about 5 minutes and noticed smoke or steam coming from the exhaust header.

I shut it off and drained the oil and the was coolant in it again, I put 3.5 quarts in and got 4.5 quarts out!

I’m at a loss, could a coolant channel in the engine block be breached?

Is there any place else that coolant could get into the oil?

Any suggestions would be appreciated.

Sorry for the long post!

(NOTE: the Chilton’s repair manual diagram shows the distributor in the wrong position for for the firing order, rotate the diagram 90º clockwise in relation to the engine block for the correct orientation)

[yellow_jacket]

Did you ever take the front cover off? Are you sure that the chain didn't wear through the front cover.

It is possible that the block is cracked. I would definetely check the front cover first.

[C-Kwik]

Did you ever take the front cover off? Are you sure that the chain didn't wear through the front cover.

It is possible that the block is cracked. I would definetely check the front cover first.

I agree here. I replaced a timing chain on a SOHC years ago and the chain had put a small hole in the front cover where the water from the pump goes through. In searching for a new front cover in junkyards most of them had the same problem. To check for this problem, you will need to remove the water pump. You can then visually and physically inspect the channel where the water pumps into the motor for any leaks. I didn't notice it when I was doing the timing chain until I felt it with my fingertips while I was cleaning the front cover. It can be very light or be a gaping hole.

[Big Red]

Good stuff folks, I didn't think of any of this!

I did everything but take the front cover off because I didn't want to mess with the oil pan.

So I take the water pump off in look in the hole where the fan blade sits?

Do I need to replace the whole block of just the cover?

Sorry if these are silly questions but I won't be able to work on the car until Tuesday so I'm trying to get a game plan together so that I can figure out what's going on in one night.

Any other possibilities?

[JNM240]

Well there are some internal water passages that might have begun leaking into the engine, as they are just sealed with gasket sealer. Looking into the water pump hole wont really get u a good look, but its a good place to start. Besides, the water pump would eventually come off with the front cover.

If it is your front cover, you will need to make sure its not cracked. If it is you can just replace that part. If its not your front cover, you may have a crack in the block, which is basically unrepairable. I hope its better news than this tho. Good luck! Keep us posted, and i have the FSM for my 90 if you need any specific info, let me know!

[Big Red]

JNM240

Will do!

Thanks a lot buddy!

[Big Red]

I called Nissan about Timing chain, guides & new cover and asked if they had revised the guides at all because when I had the chain & giudes changed in my other 240 the guides only lasted about two months before the rattling came back again.

Apparently the chain guides have been revised and now need revised mounting bolts as well, so it look's like they finally fixed the problem of the startup rattle.

[C-Kwik]

Actually, the updated guides came out many years ago. The originals were made completely of plastic. Teh new ones use metal backings. And they come with smaller bolts. I ended up using the originals. Someone else picked up the parts and I didn't figure out what the little allen bolts that were loose in the large box of parts were for until after the motor was put back together.

[Big Red]

Anyone remember what sized socket I need to remove the crankshaft bolt?, it's bigger than the camshaft bolt.

How did you loosen these bolts?

[bmxruler4130]

do you know if the timing chain problem exist in the dohc? i know it has the same block, it seems logical it would have the same problem. thanks

[yellow_jacket]

If I didn't have access to an impact, or if I can't get one in I just use a breaker bar and the starter. Very easy to do, Just brace the breaker bar against the ground and hit the starter very briefly. Just make sure you brace the breaker bar in the correct dicrection.

The Problem doesn't seem to exist in the DOHC. This is probably due to the fact that the DOHC uses two chains and so the front cover is probably a little deeper and plus the bottom chain sits in the back so it is kind of far from the front cover.

[JNM240]

Check this thread out, its helps a LOT! Besides, the crank is a 1 1/16" socket (iirc).

http://www.nissaninfiniticlub....14457

[yellow_jacket]

I think that 1 1/16 is the same as 27mm.

[Big Red]

GOT IT!

It was the cover, damm chain guides!

Looks like I'm all set, ordered all the new parts today and they get here Wednesday.

Great tip on using 5th gear to lock the engine to loosen and and tighten the bolts by the way, I have no idea why they don't put that in the book!

Thanks for all your help folks.

Chris

[JNM240]

Awesome! Remember, if you need help at ALL, ive done this before! Let me know!

[yellow_jacket]

Glad to hear you got it taken care of!

The reason that they don't put stuff like that in the book is because it doesn't always work. Personally I have had that not work. Not to mention the fact that the dealership has special tools to deal with stuff like that.