DIY: 1998 Volvo S70 GLT PCV Mod: no more smoking dipstick!

[cn90]

As promised, I finally finished brewing the heater hose in oil.
I originally soaked this heater hose back in April 2012 (brand name is Thermoid, same as the 5/8-inch heater hose mod in this thread).
This is to see how the generic rubber hose reacts to oil over time.
Well, after 2.7 years sitting in the garage, completely submerged in oil, it still looks good, soft, pliable and no issues at all.
This is to prove my point that I have been using heater hose for PCV purpose for some 25 years and have had no issues (other than the rubber hose eventually got brittle and broke after some 12y/150K...).

[kahl]

The 2000 V70 it uses the coolant to keep the hoses warm. Can I just plug up the coolant lines connectors on the thermostat and the block. Put a barbed fitting on the intake manifold then run that line direct to the PTC? I have used CN90's steps on the 94 850 and the 98 V70 and they work great.

[rspi]

Well, after 2.7 years sitting in the garage, completely submerged in oil, it still looks good, soft, pliable and no issues at all.
This is to prove my point that I have been using heater hose for PCV purpose for some 25 years and have had no issues (other than the rubber hose eventually got brittle and broke after some 12y/150K...).

This makes no sense to me, room temp oil on a rubber hose??? At any rate, if you have been using the heater hose for 25+ years, that's another story.

[kahl]

It seems on every car I do the PVC the oil tube going into the block is clogged with an asphalt like crude. I used this connection to my air compressor with good results. Hooking up a 3/4 inch hose to the stub on the lower port then filling 3/4 tube with SeaFoam then let it sit. After about an hour the asphalt debris can be blasted out. Before starting clean out all debris possible. Change oil when completed with PCV job. I think it was CN90 who said if you can blow through hose and hear bubbles the port is clear.

[Redneck]

Cn90, Can you show how you modified the plastic fitting on the right side of that hose connecting to the big air tube that goes into the intake.

[erikv11]

Redneck, are you asking about the tube to the intake on your 96 GLT? cn90s car doesn't have that, his 98 GLT is a turbo but your 96 GLT is NA. I think what you are asking about may be answered by pics in this post: https://www.matthewsvolvosite.com/forums ... 1&start=35

[hausmeister]

I want to thank the community for all the good information!

On the T5-R I bought ~2years ago the previous owner had replaced the pcv - as I could verify by re-doing it the last 2 days. It looked ok (although the parts were low quality) nothing seemed to cause the excessive smoking, this was my short term fix:

I also tested compression because I was worried, but that is fine. 12.8 - 13 bar in all cylinders.

Today I replaced everything with oem parts (probably unneccessary) and used a recommended 5/8 Oil cooler Hose to connect to the PTC valve. On the Valve I widened the holes, ~8mm was max, and for the vacuum opening I kinda added an additional hole (missed the original one). Used 6mm Silikone hose for the vac line.

Anyways it looks good, tested it today - builds nice suction in idle and also when you I rev it.


I'm kinda worried the vacuum line is to big now as you can hear it suck air and when you pinch it the engine has to compensate. Sees to run fine though. I could add something that squeezes the hose to reduce airflow, not sure if I need to.
I will try to add a vacuum check valve so that the line does not leak boost pressure. As far as I understand it is only required for vacuum under idle.
I'll just try and see if it works.

Also replaced one cam seal that was leaking, hopefully I'm leak free now.

[hausmeister]

Works fine with the check valve added - maybe unnecessary, but we want to put that boost to good use and not waste it

[Dan McBoost]

I have been battling (https://www.matthewsvolvosite.com/forums ... hp?t=73831) pressure pushing my oil dipstick up and spraying oil all over the engine, so I was looking up other catch can solutions, then found this topic.

I know I have my A and B hose reversed at the catch can, but since the catch can is open I am unsure how much that can made a difference.

BUT: Hose E is connected at EB1, then to the catch can. There is no stock check valve from E1 to EB1, what stops boost from pressurizing the catch can? Just the size of the hose??

[gilhuly]

I just did this to my 98 V70 GLT and thought I had something I could contribute to the conversation on diagnosis. I've done this operation before and the box and tubes were somewhat restricted and the PTC nipple was clogged, but the one I just did at about 145K on this car is the worst I've ever seen. The drain was completely sealed shut with dry, hard carbon/oil that had to be chipped out of both the block and the catch can. The hoses were significantly reduced. My recent symptoms developed after having done Valve stem seal replacement as I think by redoing the seals I eliminated the oil's place to go(combustion chamber on engine vacuum). The catch can was now filling up and the oil was running down the long line to the PTC and into the turbo pipe. On driving and laying into the throttle at all, as soon as I would let off the throttle I would get smoke. I did also have bad puffing out the dipstick as would be expected. I had oil working its way out the dipstick and down the ds tube and under the car. I cleaned the box which was full of all kinds of crap (chunks of crap as well as lots of chocolate milk). I used the 5/8" heater hose to replace the long run to the turbo pipe and replaced the spaghetti tube from the intake manifold with 5/32" I believe with some larger silicone tubing as adapters for the nipples. Car is back to optimal condition. Anyway my point to the board is that this symptom of smoking after coming off the throttle, going up a steep hill, hanging a hard right etc.. is likely because you have a full pcv bottle that is overflowing. In my case it didn't actually happen until I did the valve stem seals.