# Oil Dipstick Popping up



## Currancchs (Feb 24, 2011)

So, after finally resolving my slashed roof/leaking coolant (T-stat housing bolt loose :banghead I now have a new problem! The oil dipstick is popping up ~1.5'' when under full boost. Although I do not know if this is normal, there seems to be some positive pressure out of the oil cap, just enough to make it dance a bit when loose, don't know if this indicated valve issues. If the vehicle is driven easily, the dipstick stays put. In my opinion, there are three causes of this, in order of easiest to most difficult to resolve:

PCV system clogged
Valve seals leaking
Excessive blow-by (rings)

My plan of attack is to check compression (dry) and see if it is within spec/similar across all cylinders. If it is OK, I will move on to PCV system disassembly and cleaning/replacement. If low or inconsistent, I will test compression wet, if improvement is noticed, I will assume rings, but will likely take it to a shop for a full leakdown test to confirm. If it doesn't improve, I will assume valve seals, and have a shop confirm with leakdown test.

If it is the PCV system, does anybody have an opinion on the one offered by 034 motorsports, it is $190, which is cheaper than from Audi, and silicone, so maybe it would hold up better? (http://www.034motorsport.com/engine...i-tt-225-amu-reinforced-silicone-p-23169.html)

Is there anything else I should be checking, does my plan sound OK?


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## sciroccohal (May 4, 2005)

*you're not gonna like it!*

Excessive blow-by (rings) bet you a nickel! Sorry.


end of story. Valve stem seals are not in play here.

In the interest of being a senior Engineer here....you can try.

Get a big block Chevy Rocker Cover breather....these are available from moroso etc....adapt it to the oil cap hole...temporarily. They are about $15.00. Or you can make your own using new Scotchbrite pads.

your pcv system cannot handle the amount of blow-by you're generating.

dipstick still blow out= excessive blow-by created by over turboing and worn rings.


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## Currancchs (Feb 24, 2011)

sciroccohal said:


> Excessive blow-by (rings) bet you a nickel! Sorry.
> 
> 
> end of story. Valve stem seals are not in play here.
> ...


I sure hope not, but you're probably right...:banghead:

Thanks for the tip.

How common is this on a lightly modified 1.8t? I have a spec stage I clutch and 13 lbs. LW SMFW, 3'' DP, and an APR tune (~20psi spike)... The motor has 126k miles on it. I never notice oil out of the exhaust or anything like that, although it does seem to be a bit down on power (Max MAF = 190 g/s, MAF is new, have tried 3 mafs, all read similarly)...

Also, how much would be reasonable for an indy shop to charge for this job?


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## Audiguy84 (Nov 14, 2006)

A faulty pcv can cause the stick to blow out. If you think its blow by, how does the car run and how do the plugs look? Also burning any oil?


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## Currancchs (Feb 24, 2011)

Audiguy84 said:


> A faulty pcv can cause the stick to blow out. If you think its blow by, how does the car run and how do the plugs look? Also burning any oil?


Last time I pulled the plugs (~500 miles ago, but 3 months ago (car was in storage while I was working in a different state)) they looked a bit lean, but no oil deposits. Since then I've gone to a higher bar FPR and eliminated many emissions crap (SAI,N249,N112) and according to my wideband it hits ~12.5:1 AFR under WOT.

The car is running great, good power (although not great for the modifications), starts right up, no smoke out of the exhaust, ever, idle is smooth, etc. In my original post I did address that I thought it could be PCV related, just really posted this thread to make sure my steps of diagnosis were well-reasoned and if there was anything else that could/should be done/checked that would clearly pinpoint the problem. I will be pulling the plugs tomorrow, and doing a compression check, that should tell me what's going on, I will post results of that here.

One thing that I forgot to include that makes me think PCV issues is that there is some sludge on the dipstick, only in cold weather, that is not cleared during my morning commute (~45 minutes). The oil itself is not milky, and no coolant leakage. This makes me think that the crankcase is not properly being vented, because if it was being properly evacuated by the PCV system, there shouldn't be sludge like that in there, even if there was excessive blow-by (Or can blow-by cause the sludge...?)

I ordered the 034 motorsports PCV kit, so if compression checks out ok I'll replace the whole PCV system and see what happens.


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## sciroccohal (May 4, 2005)

*TEST!*

Run a compression check
Run a compression check with one *teaspoon* of 10W30 in the cyls.
Run engine vacuum with gauge.

RESULTS?????:beer:opcorn:


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## Currancchs (Feb 24, 2011)

sciroccohal said:


> Run a compression check
> Run a compression check with one *teaspoon* of 10W30 in the cyls.
> Run engine vacuum with gauge.
> 
> RESULTS?????:beer:opcorn:


Haha, perfect, took me three paragraphs to say that!

Vacuum has already been checked, fluctuates between ~18-19mmHg, taken at FPR vacuum line with MityVac handheld vacuum pump (probably not the best way to do it, but its what I had on hand)


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## sciroccohal (May 4, 2005)

*good vac.*

Running vacuum is an art. Its the needle *'twitches' *that tell you what is going on.
I'll try to get my friend the moderator to post up a '*vacuum twitching needle chart*!'

18-19 is fine.


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## Currancchs (Feb 24, 2011)

*Update*

Okay, so I ran the compression check and I'm not really sure what the results mean. I know that the one cylinder is a bit lower than the others, but feel that it may be OK/close enough, but don't really know exactly how to interpret, since this one doesn't seem obviously good or bad. Results Below:

Passenger Side Driver's Side

160psi dry --- 180psi wet/175 dry --- 200psi wet/175psi dry --- 195psi wet/175psi dry --- 205psi wet

Front of Car


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## Currancchs (Feb 24, 2011)

Anybody have an opinion on those compression test results? I will be replacing the PCV system with the full silicone kit from 034 motorsports regardless (have already purchased parts) sometime this week, or possibly next weekend and post back if this has resolved the crankcase pressurization issue in any case.


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## sciroccohal (May 4, 2005)

*rule of thumb*

A difference of 15% is becoming 'marginal'. You're at 20%. One cylinder is leaking down and causing blow-by. It's not egregious yet...just an indicator.

what did engine vacuum tell you? Was the needle steady or jumping?

do you have any oil in water or water in oil?

Did you try the 'open PCV' test?

ps regards to Nashua...I'm originally from Hanover! BRRRRR!:laugh:


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## Currancchs (Feb 24, 2011)

sciroccohal said:


> A difference of 15% is becoming 'marginal'. You're at 20%. One cylinder is leaking down and causing blow-by. It's not egregious yet...just an indicator.
> 
> what did engine vacuum tell you? Was the needle steady or jumping?
> 
> ...


Great place to live! It is getting cold here lately, although past few days have been beautiful (60's). Some snow last week though! I used to play hockey in Hanover (Nashua Panthers/Salem Saints), love NH, used to live in Dracut, MA, go to school in Concord, NH now.

I have not yet tried the open PCV test, was in a bit of a rush after doing the compression check so didn't get to it (I know its really easy and that's not really an excuse).

I have some sludge showing on the dipstick (yellow looking crap, not mixing with the oil). It didn't clear after ~45 minute highway commute, average speed ~75mph, or ~3k RPM (roughly). Coolant does not leak (after I found the external leak anyways). No signs of oil in coolant, just completely flushed the system last week with new G12.

The vacuum seems to be mostly steady, a little jumpy sometimes, especially when the auxiliary fan kicks on. When it does fluctuate it is not more than 2 mmHg of fluctuation. Definitely some fluctuation though.

As far as percentages, I could be wrong, but I thought my variance was 8.57%... Maybe I did it wrong, but here is how I calculated.

Highest Cylinder = 175 psi dry
Lowest Cylinder = 160 psi dry

100 * ((175-160)/175) = 100 * (15/175) = 100 * 0.0857 = 8.57%

If done by & of lowest cylinder:

100 * (absolute value(160-175)/160) = 100 * (15/160) = 100 * 0.9375 = 9.375%

I think many recommend 10% max for tuned motors (not that I have done a lot to this one) and my numbers put me close to that, thought it was weird though that the other three were perfect...


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## jbrehm (May 16, 2006)

His dry numbers are like 8-9%, which is fine, and easily within the margin of error anyway. OP, your compression is okay; do a warm leakdown and report back with the numbers - they will tell the story of your combustion chamber's sealing points.

And pull your PCV system to ensure that it's flowing air. VWs are notorious for their foul condensate in cold weather - it doesn't contaminate the oil, but you'll find it in catch cans, dipstick, filler cap, etc., and is often mistaken for coolant contamination in the oil since they both look similar (chocolate milk colour). If your PCV isn't flowing well/properly, you'll get more buildup. In my climate, with the boost I'm running, I need several lines with good routing to evacuate my crankcase effectively. I'm even thinking about putting in a vacuum pump.


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## Currancchs (Feb 24, 2011)

jbrehm said:


> His dry numbers are like 8-9%, which is fine, and easily within the margin of error anyway. OP, your compression is okay; do a warm leakdown and report back with the numbers - they will tell the story of your combustion chamber's sealing points.
> 
> And pull your PCV system to ensure that it's flowing air. VWs are notorious for their foul condensate in cold weather - it doesn't contaminate the oil, but you'll find it in catch cans, dipstick, filler cap, etc., and is often mistaken for coolant contamination in the oil since they both look similar (chocolate milk colour). If your PCV isn't flowing well/properly, you'll get more buildup. In my climate, with the boost I'm running, I need several lines with good routing to evacuate my crankcase effectively. I'm even thinking about putting in a vacuum pump.


Sounds good. I am pretty interested to see what the PCV system looks like at this point, not sure if it has ever been removed/cleaned by a previous owner... I did replace the PCV check valve in the T-shaped housing about a year ago (not for any reason, saw it as preventative maintenance), used a part off of German Auto Parts.com, the part was cheap, maybe that failed under the extra boost from the chip... That might allow pressure from the intake to get into the crankcase too, overlooked that in my early diagnosis...

In any case, I will be doing the whole PCV system with the new kit from 034 motorsports for AMU motors (mine is an AMU). I will also likely take pics and do a write-up, hopefully showing how clogged the stock system is, 034 is giving a free T-shirt to whoever does one first, and I enjoy free stuff... I will include a link to the new thread here if I do the write-up.

As to your extra lines, I was just thinking about the puck shaped valve on the TIP, the one with the spring loaded flap that closes under intake vacuum (before the turbo)/under boost. It has a small bypass port that allows some vacuum to be pulled out of the crankcase under WOT, but not enough that the crankcase would be exposed to serious vacuum. If that bypass port were drilled out just slightly, that should allow the crankcase to be exposed to more vacuum under WOT, but normal vacuum under all other conditions. With more blow-by from increased boost, the extra vacuum would likely be desirable, and not lead to excessive vacuum (unless you go overboard). You've probably already thought of this, but I thought it was worth mentioning.

Just out of curiosity, what problems were you experiencing that caused you to go the extra mile to improve flow of crankcase gases? Did you have a gauge tied into the crankcase to monitor pressure buildup? (Do you think this would be a good idea on an older, highly stressed motor?)

If the PCV system is OK, I will likely wait until the next time I change plugs to run a leakdown test (laziness).

Thanks to everybody for their input and Happy Veterans Day (especially to those of you that have served, thank you!)!


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## Currancchs (Feb 24, 2011)

Figured I'd post up the pictures I took of the plugs while they were out. I think they look OK, maybe a bit lean, but I the color may not be entirely accurate, as I did not go WOT, then cut ignition before doing this, the car was just driven normally, then parked and plugs removed.


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## jbrehm (May 16, 2006)

Currancchs said:


> Just out of curiosity, what problems were you experiencing that caused you to go the extra mile to improve flow of crankcase gases? Did you have a gauge tied into the crankcase to monitor pressure buildup? (Do you think this would be a good idea on an older, highly stressed motor?)



I run a lot of pressure (30+psi at the _manifold_), and have a pretty big turbo (PTE6262 - about the same size as a GT4088), so I was pushing a lot of blowby out the crank and valve-cover vents. I took the internal valve cover baffle out, drilled about 30 holes in it (it had 3 tiny holes!), filled the baffle area with some stainless steel pad (_not_ steel wool, which would drop all sorts of crap), then drilled and tapped the valve-cover and screwed the baffle back on (it was riveted). I also added a second 3/4" line to the valve cover, and run all three lines to my catch-can. It's working well so far, but I'm going to experiment with pulling a vacuum on it, either by routing back into the intake, or running an aftermarket vacuum pump.

Like I said, you should be thoroughly checking your PCV system, and running a leak down test before you get ahead of yourself.


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## 01ttgt28 (Jun 23, 2009)

I have a billet dipstick and it was popping under boost my problem was my catch can it couldn't handle 
All the boost that was my problem


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## Currancchs (Feb 24, 2011)

After installation of the 034 motorsports AMU silicon breather system, my problem seems to be resolved. The stock breather system seemed to flow pretty freely, though, although I forgot to check the suction jet pump for free flow... The PCV valve in the kit is an aluminum ball type check valve, and my stock plastic valve (bought from German Auto Parts ~1 year ago) allowed airflow in both directions freely, although maybe it sealed better under boost (looked like a rubber flap on a spring, and one side was not sitting flush at rest)?

I also replaced the dipstick tube (bought one in case the stock one snapped, it didn't, but I replaced it anyways). The new dipstick tube is a much tigher fit, my stock one was very loose (possibly also helped?).


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## Boulderhead (Oct 21, 2012)

*Go 034*



Currancchs said:


> After installation of the 034 motorsports AMU silicon breather system, my problem seems to be resolved..


:thumbup: I was quite pleased with the kit as well.. all my stock rubber was looking pretty stressed and 3 weeks with the silicon on is a nice comfort.


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