740 Wagon 1990 Head Gasket???? Not sure about this symptom

GSmith · Post by **GSmith** » 22 May 2009, 11:32

I changed the water pump on this motor 1800 miles ago. This week I started seeing oil in the coolant overflow tank. The oil seems fine (not cloudy) and the car is not blowing smoke.

Looking at the motor, I see what looks like oil seeping out where I think the head meets the block right above where the top of the water pump feeds into the block.

So:

A- Is there a separate seal where the top of the water pump goes into the block?

B- Seeing as this motor has 317,000 miles on it as of yesterday and hasn't been over-heating, could maybe I just need to change the head gasket and not replane the head? I really don't have the money to have it done. I'm hoping there's a separate seal that might be causing this.

Any ideas?

GSmith · Post by **GSmith** » 22 May 2009, 11:38

Revision to statement A above:

The seal on the top of the water pump going to the block is new. What I was hoping was there there was *another* seal that's above or near that seal and that keep the oil from going into the cooling system.

Post by **billofdurham** » 22 May 2009, 12:32

I would suspect that it is the head gasket as I can't think of any other seal that keeps the oil and water apart.

I have known of heads that didn't need to be skimmed but they have been few and far between. You will only know if it is true when you get it off and check it with a straight edge. Hopefully you will be lucky and it helps if you take out the bolts in the correct order.

Bill.

GSmith · Post by **GSmith** » 22 May 2009, 21:38

Bill,

On one of the other forums, someone mentioned the head bolts stretching on an 850 motor and that they would need to be replaced with new ones or that you would need to use washers to get the torque right when tightening. Any truth to that that you've experienced?

Also, does anyone have the instructions on removing and replacing it?

Greg

Post by **billofdurham** » 23 May 2009, 12:09

All head bolts stretch. For the 740 the recommendation is to change them after 5 head changes or if in doubt change them anyway. You will find this information in attachment 1.

Also, does anyone have the instructions on removing and replacing it?

740 Cylinder Head 1.pdf: (6.32 KiB) Downloaded 183 times

740 Cylinder Head 2.pdf: (23.53 KiB) Downloaded 145 times

740 Cylinder Head 3.pdf: (4.73 KiB) Downloaded 169 times

740 Cylinder Head 4.pdf: (37.41 KiB) Downloaded 181 times

The cylinder head height should be 5.752" (146.1mm).

Maximum warpage -
Crosswise 0.02" (0.50mm)
Lengthwise 0.04" (1.0mm)

If you need more information ask.

Bill.

GSmith · Post by **GSmith** » 23 May 2009, 18:42

Bill,

Thank you so so so so much. You're a blessing!

Greg

GSmith · Post by **GSmith** » 23 May 2009, 19:21

Bill,

I read through the documents - Documents 3 & 4 are the same documents. Should that be? They are both INTAKE MANIFOLD R & I and EXHAUST MANIFOLD R & I.

Documents 3 & 4 also refer to another document: FUEL PRESSURE RELEASE

The first document "CYLINDER HEAD R & I" refers to: TIMING BELT R & I which I don't see. Is there more?

Greg

GSmith · Post by **GSmith** » 23 May 2009, 19:27

Also, I don't see the torque specifications either....

Post by **billofdurham** » 24 May 2009, 15:15

I have a few days R & R and my whole system goes awry.

Here are the bits I missed, I hope.

740 Cylinder Head 4.pdf: (279.71 KiB) Downloaded 203 times

740 Cylinder Head 7.pdf: (221.63 KiB) Downloaded 220 times

If you need anything else just ask. Hopefully I shall be fully recovered from my R & R soon.

Bill.