Moisture under rear trunk lid

[geoff]

I recently noticed the area inside the rear trunk on my 2001 Boxster above the radiator cap is slightly moist, with a light, slick film. I already had the new style radiator cap, which was installed about a year ago when the coolant overflow reservoir was replaced. Just to be on the safe side, I replaced the radiator cap, but still have some slight moisture after driving.

I popped the cover off the oil and radiator fill caps, and even though it wasn't spotless, it was dry

The moist area is in the top of the following picture:

Any suggestions on what else to consider before taking the car to the dealer? If the coolant overflow tank is leaking, do I have to take the carpeting out to tell, or would it have been obvious from the view I have here?

What is the contraption between the oil and coolant fill openings? Is this something I should try to tighten the bolts on?

Just for information, here's the old vs. new style radiator caps:

Does anybody know if the Cayman has yet a newer style radiator cap. The two Caymans (Caymen?) I've seen at dealers have a different looking radiator cap

[renos]

I think this moisture is normal for all Boxsters I have seen, including my 2001 S.

No system can be 100% air tight, but the new type cap reduces this moisture. It is just that due to the position of the reservoir it is noticeable. In the engine bay of a front engined car you would't even notice such moisture.

If the reservoir leaked the area underneath the carpet and eventuallythe carpet itself would get wet, and you would notice loss of coolant.

[Highlander]

What is the contraption between the oil and coolant fill openings? Is this something I should try to tighten the bolts on?

The contraption is the bleed valve. You might check the bolts for snugness, but I would not advise tightening them unless one is obviously loose. If you ever need to bleed the system, pop the wire up so that it is vertical. This allows air to bleed from the system without needing the pressurised equipment the dealer uses.

Good Luck,

Graeme

Edited December 21, 2005 by Highlander

[xclusivecar]

Same problem last winter. Replaced the radiator cap to the new .01 part numbered cap and all was well. No problems since.

[Tool Pants]

http://www.pca.org/tech/tech_qa_question.a...E-32A7003D2692}

http://www.pca.org/tech/tech_qa_question.a...4-E8AFFBBBCF4F}

http://www.pca.org/tech/tech_qa_question.a...E-337BB00E2233}

I have seen a few of these messages over the years. Condensation above the service tray in the rear trunk. Some owners have been told it is normal. Heat from the bottom of the trunk lid and cold from the top.

I never thought this was normal, but I never asked one of the mechanics. I had cracks in the bottom of my tank and there was no condensation. My January 1997 had the VW/Audi cap that was used back then - not even a .00 cap. No warning sticker to screw the cap on straight. No condensation on my car.

Your car is a mystery. Tank has already been replaced. Cap replaced - but this is not clear. Your cap was replaced when the tank was replaced. Then did you just replace the cap a second time? The reason I ask is that at a tech session at an independant shop they have had new caps that did not hold pressure. When they replace a cap they test it first to make sure it is not defective.

[tholyoak]

I believe the condensation is normal. The service tray is sealed to the trunk lid so depending on how humid the air was when the trunk lid was last closed and the temp difference between the sealed service tray and the outside temp, this will dictate how much condensation you see on the inside of the lid above the tray.

Condensation varies on my lid depending on the time of year and the weather. I have the updated cap and tank and I have never had to top up the coolant since the motor swap almost 10k miles ago.

Todd

[geoff]

...

I never thought this was normal, but I never asked one of the mechanics. I had cracks in the bottom of my tank and there was no condensation. My January 1997 had the VW/Audi cap that was used back then - not even a .00 cap. No warning sticker to screw the cap on straight. No condensation on my car.

Your car is a mystery. Tank has already been replaced. Cap replaced - but this is not clear. Your cap was replaced when the tank was replaced. Then did you just replace the cap a second time? The reason I ask is that at a tech session at an independant shop they have had new caps that did not hold pressure. When they replace a cap they test it first to make sure it is not defective.

Yes, coolant cap (01 suffix) replaced at the same time as the tank about a year ago. When I started noticing moisture, I bought another coolant cap from Sunset (also 01 suffix) and replaced, but still notice moisture. I cleaned everything out, and no obvious leaks. I just lightly snugged up the bolts on the bleed valve - we'll see if that makes any difference.

Have you noticed the Cayman has yet a different looking coolant cap?

[number9ine]

You know, I have that same problem with my '03 S. Oddly, when I stopped at a dealer to point it out, the tech opened my boot, took one look at the condensation and proclaimed "it's perfectly normal."

I get exactly what you get, the slimy condensation, a black ring from the filler area seal, plus every month or so, I'll see one or two small frothy yellow-ish bits around the expansion tank cap. I've checked the cap, tank, and seating and it all looks good.

My water temps range from about 170-200 once warmed up, and I haven't noticed a significant dip in my coolant level, although the tank level is hard to read. So, until my trunk is full of leaking coolant, I'll take the Porsche dealer's word for it.

[Tool Pants]

Well, I did ask one of the mechanics. The same mechanic who told me how to replace the tank, which I did last month.

He does not consider this condensation normal. He said to snug up the 8 screws on top of the bleeder valve and see if that makes a difference.

If the picture looks strange it is because it is my old tank sitting on the driveway. I removed the 8 screws to see what was under the bleeder valve cover.

[Q-Ship986]

I have noticed this condensation, too. In the 5 months I have owned my '03, it was sporadic; hardly ever in the summer months but present more as fall arrived. (I have tucked my car away for the winter, so I haven't checked for a month.) FWIW, I don't have the bleeder valve.

Bear in mind, the trunk gets pretty warm during normal operation, but it is vented...the 'owner service center' that is sealed separately is not. I'm inclined to go with humidity and temperature differential on the sealed side versus the outer. That said, I'll be checking that expansion tank cap when I prep for the spring, though....

Could some Porsche techs, and some reading this, be unfamiliar with this situation if it is climatic?

--Brian

[adsach]

I have noticed this condensation, too. In the 5 months I have owned my '03, it was sporadic; hardly ever in the summer months but present more as fall arrived. (I have tucked my car away for the winter, so I haven't checked for a month.) FWIW, I don't have the bleeder valve.

Bear in mind, the trunk gets pretty warm during normal operation, but it is vented...the 'owner service center' that is sealed separately is not. I'm inclined to go with humidity and temperature differential on the sealed side versus the outer. That said, I'll be checking that expansion tank cap when I prep for the spring, though....

Could some Porsche techs, and some reading this, be unfamiliar with this situation if it is climatic?

--Brian

I never had condensation living in Arizona(dry).

I had condensation ONCE living in Albany, NY(less dry).

I tightened the cap after seeing condensation and it hasn't come back in 2 years(still in Albany, but moving to Boston next month)

Considering what happened to ToolPants, I sure hope that was OK to put in print :lol:

[qbranch]

I believe that this condensation is perfectly normal. I get this on my Boxster the whole time, especially at this time of year. Mind you, it rains a lot in London, so it's quite reasonable to think that there would be a fair amount of moisture trapped in this sealed section.

regards,

Rich

[Tool Pants]

FWIW, I don't have the bleeder valve.

--Brian

You have the valve but cannot see it unless you remove this cover.

[Q-Ship986]

Thanks...I was beginning to wonder about that. --Brian

[geoff]

Tightening the bolts holding the bleeder valve hasn't helped with the moisture (slime) on thr trunk lid above the coolant cap. Dealer service manager said it is normal, and mine is much drier than most. On another (less technical) Boxster board the other week, I saw a posting by somebody suggesting replacing the two rubber O-rings inside the bleeder valve. Part numbers listed were 999-707-370-40 and 999-707-371-40. Has anyone replaced these and found it solves the moisture problem? The guy who posted thought he disturbed something when he replaced his water pump, and this procedure solved his problem. At less than $2 for the O-rings, I might try it.

How tight do I tighten the bolts on top of the bleeder valve (torque setting)? Nothing mentioned about this in the Bentley manual. Anybody know the recommended tightness (other than "just snug enough")?

[Q-Ship986]

Tightening the bolts holding the bleeder valve hasn't helped with the moisture (slime) on thr trunk lid above the coolant cap. Dealer service manager said it is normal, and mine is much drier than most. On another (less technical) Boxster board the other week, I saw a posting by somebody suggesting replacing the two rubber O-rings inside the bleeder valve. Part numbers listed were 999-707-370-40 and 999-707-371-40. Has anyone replaced these and found it solves the moisture problem? The guy who posted thought he disturbed something when he replaced his water pump, and this procedure solved his problem. At less than $2 for the O-rings, I might try it.

How tight do I tighten the bolts on top of the bleeder valve (torque setting)? Nothing mentioned about this in the Bentley manual. Anybody know the recommended tightness (other than "just snug enough")?

Are you having this occur consistently? If so, then maybe the o-rings are worth a (cheap) shot. Fill us in, afterwards. I saw the posting on ppbb, too, but wondered how likely it is that moisture from the coolant system is getting by two o-rings squeezed by 8 bolts (unless they are loose, duh). I have noticed moisture, too; but I thought it was water (i.e., without coolant residue) and assumed it was environmental/seasonal. There must be a reason for the nice gasket around that 'service center'--it sure isn't there to keep the heat out of the trunk.

Regarding the bolts on bleeder valve, I don't have the specs, but my shadetree instincts tell me they look like the type of fastener, grouped with others, that doesn't require much torque. Hand tighten with a 1/4-inch socket wrench is my gut feel.

--Brian

[Q-Ship986]

Then again, PCA's Scott Slauson seems convinced condensation should never be present....

http://www.pca.org/tech/tech_qa_question.a...B-3E3CE7B566EB}

--Brian

[Tool Pants]

Just a note.

My January 1997 original tank did not have o-rings for the bleeder. Instead, it had a rubber diaphragm, thus this picture.

Looks like a bleed valve change hapened for model year 1998.

Since my replacement tank is a .07 then I should now have the bleed valve with the o-rings.

[skill]

coolent problems on the boxster cause so many problems..it certainly has hit my wallet hard.