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

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cn90
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Year and Model: 1998 S70 GLT
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DIY: 1998 Volvo S70 GLT PCV Mod: no more smoking dipstick!

Postby cn90 » Fri Dec 14, 2012 4:23 pm

DIY: 1998 Volvo S70 GLT PCV Modification, how to get rid of smoking dipstick!

There are a few threads/DIYs on how to overhaul the PCV (See REFERENCES section below).

Many people overhauled the PCV only to find out they still have smoking dipstick (no increased in PCV pressure but simply smoking dipstick, whose significance is unknown).

Some people install a snorkel tube out of a modified oil cap ---> intake (ugly looking but works).

Some use plumbing copper pipe to replace the plastic pipe, seemed to work.

My PCV was performed by the Volvo dealer 2 years ago (by previous owner), and from looking at the previous service records, they did a half job. I overhauled the PCV again and found the 2-year-old plastic pipe (from oil trap ---> intake) broken, piece of junk. Read on…

After I modified this plastic pipe (ID = 3/8”) with standard heater hose (ID = 5/8”), the smoking dipstick issue is solved!!!

My theory (see sketch below), my numbers are arbitrary strictly for illustrative purposes:
- Let’s say from factory, the engine blow-by rate (volume/minute) is 4 for Top hose and 4 for crankcase hose, and let’s say the 3/8” pipe was designed to carry a rate of 10, then the PCV system works fine from factory with a margin of 2.
- As the engine ages (mine has 150K), the piston clearance increases, the valve stem seals are not as tight, now there is increased crankcase pressure that the factory setup cannot handle ---> smoking dipstick.
- So the engine with 150K miles blow-by rate (volume/minute) is now 8 for Top hose and 8 for crankcase hose, and since the 3/8” pipe can only handle 10 ---> crankcase pressure builds up! By using 5/8” heater hose, the diameter is increased by a factor of 5/8 divided by 3/8 = 1.67; surface area is increased by 2.77 times, so now the flow is 27.7 instead of 10. Remember surface area = pi r^2 (high school stuff).


VolvoPCV01a.JPG



PARTS For 1998 S70 GLT

- Heater Hose with ID = 5/8”, $6 for 6-foot roll at Advance Auto Parts.
- 956561...Oetiker clamp...qty = 4; $1.94 x4
- 976584...Oetiker clamp...qty = 2; $2.00 x2
- 977964...Oetiker clamp...qty = 2; $2.58 x 2

- 8653339...Short hose to engine block...$5.85
- 1271653..Short hose to engine block... qty = 1; $8.76

- 1271654..Hose to top of engine... qty = 1; $21.24
(I guess you can use heater hose here, just a guess)

- 1271988...Oil trap $29.88

- 9146266...Intake manifold gasket... $13.86

---> 9471644...piece of junk, save $40 for beer! This PN has 2 items: 3/8” pipe and vacuum hose. Do NOT buy this for 2 reasons:
a. The plastic pipe will break in 2-3 years.
b. The pipe is too restrictive for high mileage vehicle.
Instead, use 5/8” heater hose as I mentioned above. For the vacuum hose: use standard vacuum hose.



TOOLS

For Tools, see the other DIYs listed in REFERENCES section below. The bottom line is:
- Some 10-mm, 12-mm sockets, wrenches. Box wrenches are useful here!
- Iron Pipe (for stubborn bolts, I slide the ratchet inside the iron pipe for added leverage) or 3/8” breaker bar
- 3/8” Universal joint is a must-have!
- Telescopic magnet to retrieve dropped bolts!
- Oetiker clamp crimp tool (about $10, go to Sprinkler section at Home Depot)
- Grease/antiseize for the bolts
- Blue Masking Tape for marking hoses etc.


PROCEDURE (Abbreviated Version)

- This has been discussed in the other DIYs, so I won’t go into detail. Instead, I will only highlight the important tricks of the trade:

1. Get some blue masking tape, any part that is disconnected, put blue tape on so it is easy to know that part needs to be re-connected.

2. Label all bolts removed.

3. D/C battery (check your radio code).

4. D/C Turbo hoses (via clamps) and set aside.

5. De-pressurize fuel system 1st via Schrader valve, then disconnect fuel line using 14-mm/17-mm wrenches as shown. If you have the EVAP fuel line (like mine), then later you need to undo the 2 bolts holding the fuel rail/injectors, gently lift that up and ease the EVAP line out a bit. Don’t disturb the fuel injectors too much.


VolvoPCV01.JPG



6. The Intake Manifold has 3 UPPER bolts and 4 LOWER bolts and two (2) more bolts from underneath.
- Remove the 3 UPPER bolts using 10-mm socket with swivel and telescoping magnet.
- Note that I put some paper towel under the bolt to catch it from dropping down.

- Do NOT remove the 4 LOWER bolts, loosen them a few turns only.

- Underneath the Intake Manifold: reach your hand down, there are two (2) 12-mm bolts holding the Manifold to the L-shaped bracket(longer bolt) and Engine Oil Dipstick (shorter bolt). If they don’t come out, get a socket and long extension passing in front of the subframe and come from underneath with breaker bar (R hand hold socket/swivel extension; L hand holding ratchet/break bar). No need to have car on ramp. I did all this job from above.


VolvoPCV02.JPG



VolvoPCV03.JPG



7. Lift the Manifold upward and rest it on iron pipe as shown. During this process, watch the throttle side to be sure no hoses are strained. If in doubt, disconnect appropriate vacuum hose(s) and label them with blue tape. I d/c the connector to the idle valve.

8. Note the Oil Trap and its connections. Note the following:
- Rad hose is tied out of the way (cushioned by some paper towel to prevent string from cutting into rad hose).
- EVAP line is moved out of the way.
- L-shaped bracket that supports the bottom of the manifold.
- Manifold rests on iron pipe.
- The Manifold pass side nipple, connect the vacuum elbow before re-installing the Manifold!


VolvoPCV04.JPG



9. Note Intake Valves don’t look too bad at 150K miles.


VolvoPCV06.JPG



10. Once the oil trap is removed, get the heater hose and connect to the “Oil Return” Port, blow through it: if you hear air bubbling inside the oil pan, then this port is open. Mine was wide open.
(The Volvo dealer told the P.O. that he had smoking dipstick and the oil pan needs to be dropped for inspection, and they quoted 4h of labor and $600! As you can see, this is a simple test from above, no need to drop the oil pan!).


VolvoPCV07.JPG



11. Plumb all the connections on the oil trap before install. This will make your life easier.
- Now this is the time to get rid of factory 3/8” pipe and replace with 5/8” Heater Hose. This will increase the flow by a factor of 2.77!
- Make sure the heater hose is 2-3 inches longer than factory length. This way you can trim it later where it enters the intake.


VolvoPCV05.JPG



VolvoPCV08.JPG




12. Alright, as they say installation is the reverse of removal.
- Do not forget to re-connect the fuel line and EVAP line.
- Install the vacuum elbow on the pass side of the Intake Manifold before install!
- Use new Intake Manifold gasket.

---> For the L-shaped bracket holding the bottom of the Manifold:
- Once the Manifold is properly tightened and secured by its 7 bolts, install the 12-mm bolt from the L-shaped bracket ---> bottom of the Manifold (note this is the longer bolt, the shorter bolt is for the dipstick housing); then install the 2nd 12-mm bolt from the bracket to the engine block.
- Don't forget the dipstick housing bolt that goes underneath the I.M.

- Use antiseize/grease for the bolts.
- Prime the fuel system before cranking (leave key in position II for 30 sec).
- Visually check all hoses/blue tape and make sure all are connected.


CONCLUSION

- Went for a long drive at night, came back home, opened the hood, guess what: no more smoking dipstick!

- So the morale of this long story is: this mod (getting rid of factory 3/8” pipe using 5/8” heater hose) solved the smoking dipstick mystery!


REFERENCES

PCV System Repair on a Volvo 5-cylinder (by “jblackburn”)
viewtopic.php?t=28487

My previous PCV for NA engine:
viewtopic.php?f=1&t=28334

Discussion on what parts to buy:
viewtopic.php?f=1&t=53363
1998 S70 GLT 160K+
2005 XC90 2.5T 85K+

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jblackburn
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Re: DIY: 1998 Volvo S70 GLT PCV Mod: no more smoking dipstic

Postby jblackburn » Fri Dec 14, 2012 4:32 pm

So you'd done the typical PCV repair and it ended up still smoking? If so, good to know this solves that!
'98 S70 T5
2012 Chevy Cruze LT 6MT


A learning experience is one of those things that says, "You know that thing you just did? Don't do that."

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cn90
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Re: DIY: 1998 Volvo S70 GLT PCV Mod: no more smoking dipstic

Postby cn90 » Fri Dec 14, 2012 4:37 pm

Yep,

The factory 3/8" pipe was the culprit.
This (5/8" heater hose) is a permanent fix for high mileage vehicles!
I am very happy with the result, absolutely no smoke coming out of dipstick.
1998 S70 GLT 160K+
2005 XC90 2.5T 85K+

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jblackburn
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Re: DIY: 1998 Volvo S70 GLT PCV Mod: no more smoking dipstic

Postby jblackburn » Fri Dec 14, 2012 4:46 pm

Nice! Good to know this simple fix will let the otherwise-stock PCV system handle increased blowby by providing more vacuum.

(At least in a turbo engine!)
'98 S70 T5
2012 Chevy Cruze LT 6MT


A learning experience is one of those things that says, "You know that thing you just did? Don't do that."

mercuic: Long live the tractor motor!

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Re: DIY: 1998 Volvo S70 GLT PCV Mod: no more smoking dipstic

Postby xHeart » Fri Dec 14, 2012 5:40 pm

This is a comprehensive write up, long overdue after our Justin's breakthrough several years ago.
Author cn90 painstakingly delineate and makes reference to the historic development of this critical DIY.

A DIYer myself, though It may appear obvious to many, I would ask the author to add the OE/OEM part # for seals and gaskets for the filler cap, and complete dipstick assembly to make this a foremost write up on this topic.

Top it off with oil change procedure.
--
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Past: German Shepherd | 1989 Volvo 740 GL | 1979 Volvo 240

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cn90
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Re: DIY: 1998 Volvo S70 GLT PCV Mod: no more smoking dipstic

Postby cn90 » Fri Dec 14, 2012 6:29 pm

OK xHeart,

Ask and You Shall Receive haha.

- Oil Filler Cap GASKET PN 1275379, $5 at Volvo dealer.

- Dipstick is a sticky topic for the 1998+ S/V70 models. PN 1271921 is no longer available, but I ordered 1271920, guess what, the label says 1271920 but the dipstick clearly has 1271921 engraved on it!
Read more in this thread:

viewtopic.php?f=1&t=18739
1998 S70 GLT 160K+
2005 XC90 2.5T 85K+

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Re: DIY: 1998 Volvo S70 GLT PCV Mod: no more smoking dipstic

Postby osman » Fri Dec 14, 2012 10:16 pm

I found this out the hard way when FCP Groton sent me the wrong hoses in my PCV kit. I had a 97 850 GLT wagon as we all know the 97 and up GLT's are all Low Pressure Turbos. They sent me the hoses for a NA type throttle body attachment as upposed to the long one which goes to the turbo breather hose. This was even after the sales rep made me read of the VIN and the engine serial number on the timing belt cover (which is usually long gone by the time I get these cars) As I was on Xmas vacation in rural alabama 16 hours away from my Texas Euro Car Ranch and didnt have the time or the desire to engage in the lenghty and costly return policy i made a quick trip to the hardware store (only thing open on sunday in my parents small town) bought and cut some 5/8 heater hose and some usable old-fashioned clamps. I hate those one-time, (not gonna attempt the name) clamps. Plus that stuff is good to have around for heater core bypasses.
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Re: DIY: 1998 Volvo S70 GLT PCV Mod: no more smoking dipstic

Postby erikv11 » Sat Dec 15, 2012 12:04 am

Yeah, people have been posting the same things about PCV over and over the last few weeks, but maybe good to have them all in one thread, here would be my points:

- Oil trap. 99% of the time, there is no need to replace the oil trap. It is hollow and durable. If it is clogged, clean it. If you must replace it, just buy a cheap one, it is hard plastic and there is no history of the cheapies breaking.

- Breather hose to the IM nipple. This was posted by Matthew1 over a year ago: wide (5/16) diameter, cheap vacuum hose is a great solution. Lasts longer, breathes better, is cheaper and easier to work with than hard plastic tubing. Just route it around the front, no need to tuck it behind the IM. This goes for NA or turbo engines, but for a turbo you need a longer hose to reach to the PTC.

- Breather hose from the trap to the intake. keaton (not sure of his username at MVS) has been preaching for a couple years to just use flexible copper pipe, and that no matter what you use, the bigger the diameter the better. Now cn90 brings the heater hose idea, this is a good and cheap solution. Eliminates the need for rubber elbow hoses.

- Clamps. many people despise Oetiker clamps, some people love them. Standard screw clamps are cheaper and work just fine and since I always have some around, I use them for PCV.

- Parts from Volvo. So there are almost always only 3 parts that you must mail order, and as cn90 posted these should come from Volvo:
8653339 short hose to engine block
1271653 hose to engine block
1271654 hose to top of engine

- Also, clean the throttle body while you have the intake manifold off. If you are going to remove it to clean it, get a throttle body gasket, they run like $1.75 each.

- Never, ever buy any rubber hoses from URO parts. Their oil trap is fine.
'96 NA 855 | 129 k
'95 T5-R 854 | 180 k
'98 V70 GLT | 15g turbo | 251 k
'98 S70 NA | 174 k
gone: '96 NA 850 210k, '98 NA V70 182k

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Re: DIY: 1998 Volvo S70 GLT PCV Mod: no more smoking dipstic

Postby binglax09 » Tue Dec 18, 2012 5:16 pm

This is Keaton85 from VS....

Here is my quick run down.

To start, great write-up! hopefully someday it will just be common place to never use the stock hose for this application.

- The copper tubing idea that I used a while back was due to having a big spool of it left over from a construction job. It's what I had and I love being able to use it since it can be cleaned and I wont ever have to worry about it again. The heater hose, though, is a much better idea since you don't have to mess with the original 90degree ends from the whole system and it can bend around the block very easily. Once I run out of the copper tubing, this is probably what I will use. Although, is the heater hose rated for constant contact with oil and fuel vapor? If not, the hose will cause more issues later on down the road.

- In my opinion, it is not this hose that is the cause of the smoking dipstick. The cause of the smoking dipstick is the small vacuum line that runs from the intake manifold to the PTC fitting at the turbo inlet. This hose is what controls crankcase pressure at idle, then once the throttle is opened and the turbo starts in, the little hole leading into the intake tube creates the vacuum to release crankcase pressure. So no matter how large the main hose is, the little hole on the PTC leading into the intake tube is what controls the amount of "suction" on the crankcase ventilation system.

- By upgrading the vacuum line from the intake to the PTC, you create more vacuum on the crankcase during idle, thus removing the residual "smoking dipstick" issue. This is where the restriction is in the stock system. The original vacuum line for the system is extremely small and can not handle an older motors increased crankcase pressure.

Side notes:
- The oil trap can be reused sometimes! I have had ones that it's worth every penny to buy new as they were so clogged that it would have been almost impossible to clean.
- Use zip-ties rated for 185degree temps instead of metal clamps. it makes the job a lot easier and you don't risk tearing the rubber hoses.
- The side hose to the block, the top hose to the head and the new bottom fitting for the drain almost always need to be replaced.
- Always replace the intake gasket!!!!
- I personally like routing all the hoses under the intake to keep them out of the way.
- don't use silicone for the vacuum line on this, it will work just fine but starts to sweat oil and getting all slimy on the outside.
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Re: DIY: 1998 Volvo S70 GLT PCV Mod: no more smoking dipstic

Postby cn90 » Tue Dec 18, 2012 5:28 pm

binglax09,

Thanks for your input, I learned the copper piping from your post. I appreciated it.

The reason I think 5/8" heater hose (yes I have been using the heater hose for PCV in many many cars in 25 years, zero problem, it is rated for oil etc.) works in getting of smoking dipstick is that: even people with NA non-turbo engine still had the smoking dipstick after a complete overhaul of the PCV.

It took me a while to go through the engineering aspect of the PCV and came up with that theory (that the factory 3/8" pipe is too restrictive). I took the Volvo factory 3/8" pipe and blew through it, it was OK, but when I blew through the 5/8" heater hose, wow, the flow was nice! Anyway, just a theory.

All I can say is I am very happy, no more smoking dipstick!
1998 S70 GLT 160K+
2005 XC90 2.5T 85K+


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