Head Gasket - Overheat Problem Identification??

Fordman · Post by **Fordman** » 01 Jun 2009, 20:40

V70 1998 Turbo, 144K
Before head removal......
A) Symptoms
1) sucking small amounts of rad fluid for the last 17k (started adding rad fluid ~ 2 years ago (127K)
2) P0305 (misfire, 5th cylinder), P0116 OBDII repeated error code
3) yellow bluish Blok-Chek test (presence of exhaust gases in rad fluid)
4) rad fluid forcing its way out of new 22 psi expansion tank cap after car is off (with cap on)
5) visible bubbles at surface of expansion tank while motor is running (w/ cap off)
6) 215F OBDII reading while idling
7) while driving, the temp reading is always normal - center of temp gauge

B) Note, in the last 10k miles have
- new expansion tank & cap
- new 180F thermostat
- new rad cooling sending sensor
- new radiator (141k, because the plastic intake tube broke but the motor was turned off as soon as the problem was noticed)
- new spark plugs-cap-rotor-plug wires-air filter

6 weeks from starting head removal - head off.....Just looking for (1) does this head gasket look ok? (2) if head gasket ok, what else is suspect.....thanks
Head off.....pics
Cylinder 3-4-5....note magenta circle......why blocked?

: V70 1998 3-4-5.JPG (82.39 KiB) Viewed 5942 times

Cylinder 1-2-3

: V70 1998 1-2-3.JPG (115.37 KiB) Viewed 5916 times

Don't like rad fluid in head bolt hole?

: 1-2 Bolt Hole Rad Fluid.JPG (79.28 KiB) Viewed 5931 times

Post by **Ozark Lee** » 01 Jun 2009, 20:55

It is hard to tell from the pictures but it looks like the head gasket has a crack on the ring at about the 4:30 position on cylinder 3. The color of the gasket looks a bit funny in that area as well. It may just be from the flash on the camera but scrutinize that area.

At this point check the head for being true and put a new gasket on with new bolts - you are beyond the point of no return on the old head gasket anyway.

The coolant in the bolt hole is as a result of taking the head off, the coolant just drained out from the head wherever it could go. Obviously, suck it all out before replacing the bolts.

...Lee

Fordman · Post by **Fordman** » 08 Jun 2009, 22:07

Saga continues.....
A pro reviews the head gasket.....so far, so good....
The next idea is a 'bad' head to cause the above symptoms..

: 321.JPG (256.62 KiB) Viewed 5911 times

: 543.JPG (266.05 KiB) Viewed 5898 times

Fordman · Post by **Fordman** » 23 Jun 2009, 21:59

6/23/9
Machinist report - the head is good, passed pressure and leak tests.

Next, water pump removal - but a bad water pump doesn't induce cd gases....so the next step, inspect cylinder walls.

Fordman · Post by **Fordman** » 27 Jun 2009, 19:46

FYI

W/ head pressure test by reputable machine shop in SLO = ok (test & valve job ~$850)
next likely suspect = turbo charger

Does any one know a diagram of how turbo can bridge exhaust gases and rad fluid?

Thank you.

-Fordman

Craigd2599 · Post by **Craigd2599** » 28 Jun 2009, 05:42

I had a similar issue with my 850 N/A turned out it was a pin hole in the gasket and nothing more. If you aren't overheating and you aren't blowing the telltale sweet white fog out the tailpipe, you have a pinhole leak in the gasket somewhere. I too replaced my radiator and that's where the troubles began for me. I am assuming, in hindsight, that the pinhole was there for quite a while but the leaky rad kept the system from fully pressurizing. Once I had a good rad and a new ex tank it found the leak for me. I could vent the pressure after I shut the car off and she ran like there was no problem. but if I left the system pressurized after shutting her down, number 3 and 4 would fill up in about 15 minutes (not all the way up mind you) and she would start very hard and sputter and you could smell the anti freeze burning. She'd then clear up and run just fine. I think you found your trouble spot and can button her up.
I posted here yesterday about one issue we did find, clean your oils passages in the head before she goes mack on. Your machine shop probably did this for you.

Fordman · Post by **Fordman** » 25 Jul 2009, 23:29

Craig,
Thank you for your reply. I agree, cylinder #5 'pin hole' is the only logical explanation for the problem. Both the cylinder head and turbo have been rebuilt. Only evidence is #5 cylinder cleaned up easly.

Fordman · Post by **Fordman** » 25 Jul 2009, 23:32

New head gasket, old head gasket - ready to install

Fordman · Post by **Fordman** » 01 Aug 2009, 16:17

Howdy all.....
Cleaning up the turbo intake hose, would like to clean the sensor shown below rather than paying $100 for a new turbo intake hose, sensor comes w/ hose. Not sure if this sensor can be separated from the hose and replaced or if I can just clean it while connected (would also like to know the theory of operation). If it can be separated does anyone know of a vendor who could sell one? Nice and clogged on the inside.
Thanks!
-Fordman

Post by **tailor** » 05 Aug 2009, 07:37

From my meagre experience it is not wise to remove the bayonet connector you have pictured. It can be put back, but I do not believe it was made to be removed in the first place. It is best to clean it with, some say, small amounts of petrol, or "deep creep" from Sea foam and even break cleaner, no doubt there may be other products. The little side hole and inside centre hole are usually the ones that get clogged, BTW your connector does not look too bad. What ever you use, DO NOT use throttle body cleaner to remove the varnish, I used it near soft rubber hoses and it made the hose all soft and mushy and had to be replaced.....you did ask!

The part in question usually suffers from a "rotten" rubber grommet, which by the way nobody will sell separately. A new hose would then be required, for anyone else reading this who now has the need to replace the "concertina hose" aka Turbo hose, If you have to order a new hose, it comes with extra ports as standard, my 94 turbo, does not need them all, so they need to be capped off, get these caps from the seller or dealer as the generic ones I bought are lousy and tear in no time and they are not expensive.