96 850 Turbo Wagon Mechanic's Challenge

[renns]

I found a vacuum line that comes thru the firewall with a wiring harness located below the fuse compartment box. It breaks away from the wiring harness and then goes downward along the brake booster, past the brake booster vacuum port and continues downward out of sight. Is this possibly the vacuum line that connects to the boost gauge on the instrument cluster?

That line is likely to power the cruise control actuator in the footwell.

Also I found something near the turbo that was referred to as a PTC on another thread? There appears to be an electrical connection to it? Is this associated with EGR?

Not EGR - crankcase ventilation. Blowby gasses are pulled out of the crankcase, through the PTC into the intake system to be burned. The PTC is a heater element where the gasses enter the main airstream. I suspect moisture in the crankcase could condense and freeze in that fitting, plugging it in certain conditions. The heater prevents that from happening.

[precopster]

Vadis number differences on the water pump bolts could mean the sealant is applied to a different section of the thread, not necessarily that they are different lengths. If you apply part number 979090 to VolvoWholesaleParts website, which incidentally is Volvo Dallas, you will find that the number supercedes to 985151 and suits both the water pump and the flange.

Easy enough to fit a 32mm bolt which has been cleaned and place the sealant (or is it threadlock) to where you think is correct.

[FlipIt]

I found a vacuum line that comes thru the firewall with a wiring harness located below the fuse compartment box. It breaks away from the wiring harness and then goes downward along the brake booster, past the brake booster vacuum port and continues downward out of sight. Is this possibly the vacuum line that connects to the boost gauge on the instrument cluster?

That line is likely to power the cruise control actuator in the footwell.

I believe the line that runs along the inner fender with the hood control cable is the one that connects the cruise control to the cruise control vacuum pump under the battery.

Also I found something near the turbo that was referred to as a PTC on another thread? There appears to be an electrical connection to it? Is this associated with EGR?

Not EGR - crankcase ventilation. Blowby gasses are pulled out of the crankcase, through the PTC into the intake system to be burned. The PTC is a heater element where the gasses enter the main airstream. I suspect moisture in the crankcase could condense and freeze in that fitting, plugging it in certain conditions. The heater prevents that from happening.

Interesting. That explains the electrical connection. Since I need to reroute the heater hoses I'll dig deeper into that area. I found a length of vacuum hose with one end broken off in the box of parts that came with the wagon. The other end has a clamp on it so it connects to a fitting somewhere. I doubt the hose is long enough to reach the vacuum "tree" on the intake manifold where the IAC valve connects. VADIS shows the hose going from the turbo toward the firewall but doesn't identify where it connects. It's not one of the hoses that connect to the TCV.

[FlipIt]

Vadis number differences on the water pump bolts could mean the sealant is applied to a different section of the thread, not necessarily that they are different lengths. If you apply part number 979090 to VolvoWholesaleParts website, which incidentally is Volvo Dallas, you will find that the number supercedes to 985151 and suits both the water pump and the flange.

Easy enough to fit a 32mm bolt which has been cleaned and place the sealant (or is it threadlock) to where you think is correct.

I used a long bolt to test the thread size of the coolant pipe flange to head bolt. M8-1.25 (the same as the exhaust manifold bolts) seems to be the correct size. I can buy flange bolts in that thread locally. I suspect that the gasket Advance Auto ordered is the wrong part. It is listed as the coolant pipe gasket but the price ($8) is significantly more expensive than the dealer list price ($3). It may be a kit that includes the large rubber O ring. From now on I think I'll just order parts on line. I have used Tascaparts for my Explorer and they also sell Volvo parts. Thanks for the link to Volvo Dallas. I thought they were local pick up only.

[FlipIt]

I took a photo of the vacuum hose routing diagram on the hood and studied it for a while. I realized it is different from others posted on the forum.

VacRout.jpg (30.22 KiB) Viewed 1945 times

Until now I had assumed that the cruise control had a connection to the intake vacuum and the cruise control vacuum pump was supplementary. However, the vacuum routing diagram shows no connection for the cruise control. It does show a line from the Pressure Gauge in the lower right to the vacuum "tree" so that's probably the line I assumed went to the cruise control. I'll hook my hand vacuum pump to the line to see if I can move the boost gauge. The hose that is broken off is the one that connects the turbo bypass valve to the intake manifold port near the throttle body. The length of broken hose in the parts box is about right to reach that distance so that's how I'll connect the new hose.

I removed the air filter enclosure to get better access to the heater hose coils. The compressor inlet hose was in the way so I decided to remove it from the turbo. I was unable to access where the clamp is from any position working from above or below the engine compartment. The hose must have been installed on the turbo prior to installing the turbo so I was forced to just work around it. I found what was left of the metal fitting that normally plugs into the firewall lower heater hose connection. 5/8 inch heater hose was fed thru the firewall openings (maybe the fittings broke or couldn't be separated) and about 12 inches of hose was coiled around the turbo. I'm in the process of cutting out the excess and routing the hoses down and away from the turbo.

[FlipIt]

Using my hand vacuum pump I was able to confirm which hose goes to the boost gauge by deflecting the needle. However, the hose will not hold vacuum even though I replaced the deteriorated flexible sections. I'm a little concerned about unmetered air (vacuum leaks) leaning the air/fuel mixture at idle. I probably should disconnect the hose from the gauge working under the dash and test the gauge and the total length of hose but that sounds like a very uncomfortable thing to do.

[FlipIt]

The coolant pipe gasket arrived Wednesday afternoon and I spent Thursday, Friday and part of today installing it. I suspended the gasket with a string tied above the head, threaded thru one of the gasket bolt holes, back up around a pipe above the head and down where I could pull while under the vehicle. I guided it between the coolant pipe flange and the head with a long screwdriver as I slowly pulled the string. Once in position I inserted some long, slender bolts thru the flange to hold the gasket in place while I carefully pulled the string out of the gasket. I soon found that the M7-1.0x20 mm bolts I had purchased were too short. I had one spare 30mm bolt that I added a washer to and inserted in the lower hole. Then I robbed a 30mm flange bolt from one of the camshaft sprockets for the upper fastener. There is a slow drip after I snugged the bolts and added water to the cooling system. I'll torque the bolts properly once I get the correct flange bolts from an online dealer.

The engine started easily and idled smoothly while warming up. The only type of leak I don't have is fuel. There's an ATF leak as previously described, the coolant leak drip, an engine oil leak that drips from the rear of the oil pan near the drain plug, and one or more exhaust leaks. I didn't have time to locate the origins of the newly detected leaks nor check the turbo for oil or coolant leaks. I'm disappointed about the exhaust leak(s) because I have torqued the exhaust manifold stud nuts to specification. I'll listen with a hose to try and determine if the leaks are between the manifold and the head, the manifold and the turbo or the turbo and the downpipe. I wouldn't be surprised if the previous mechanic reused the exhaust manifold gaskets or even left one or more (there are 5) of them out.

I only had time for the engine to idle about 10 minutes so it didn't reach normal operating temperature. Even so, I pulled the plugs, disabled the fuel pump and ignition and checked the compression. For each cylinder the compression maximized after 5 compressions as follows:
1: 125
2: 138
3: 142
4: 153
5: 117

I was glad to see that #5 had increased from the previous 60 psi to 117 but all cylinders are below the specified 156 to 185 psi. I know from previous testing that the compression will increase if I add oil which indicates poor piston compression ring sealing. I'm thinking about adding a measured amount of Sea Foam to each cylinder and letting it soak the top ring for several days while cranking the engine each day. Since the engine has only run for 10 minutes after sitting for more than a year I'm not willing to pull it for rebuild at this point.

[thecheat]

I layed out what I think are heat shield related parts on the breakfast table.

Your wife must LOVE you I wish I had half the automotive knowhow and 1/16 as understanding of a wife as you do! Good luck with your project!

[FlipIt]

This morning I purchased my first bottle of Sea Foam in my entire life and dropped two teaspoon fulls into each cylinder. This afternoon I rotated the engine about ten revolutions and added two more teaspoon fulls into each cylinder.

I noticed that the nuts on the downpipe to turbo were different sizes and not tight. I replaced the 12 and 13 mm head hex nuts with 13mm flange head hex nuts and tightened them to about 25 lb-ft. I couldn't tell by looking if there is a gasket between the turbo and the exhaust manifold or if there are gaskets between the exhaust manifold and the head.

By looking at wetness the engine oil leak doesn't appear to be coming from a camshaft seal, the turbo or the drain plug. It possibly is leaking between the oil pan and the block. The oil pan bolts were all snug but several were not torqued to specification. I tightened them and then cleaned the area with a rag for the next engine run test. Maybe the crankcase pressure is high. I may see if removing the dipstick has any effect on the leak.

The ABS light stayed illuminated on the instrument panel when the engine ran for 10 minutes. I may have disturbed the electrical connector to the main unit when working in that area. The only DTC that was set was P0444, EVAP emission control system purge valve C open.

The boost gauge deflected toward the vacuum side when the engine was idling.

[Ozark Lee]

Assuming that you don't have an ABS problem the light will not reset until you hit about 20 MPH as you drive away and that is perfectly normal.

Don't loose any sleep over that one until you drive the car.

...Lee