Intercooler Cleaning

OK- I cleaned the intercooler today as instructed in FAQ - when I removed the hose from the intercooler (underneath), ABOUT A 1/4 CUP OF OIL CAME OUT. The heat exchanger was totally full with oil. Everything is buttoned back up, car runs fine. Do I have a problem with the PCV valve?

96 Passat TDI
56k miles

Every turbo charged car whether diesel or gasoline has a PCV problem. Ask mickey about his PCV Elephant Hose modification.

I'm guessing you've got quite a few miles on that '96. It's not surprising that the IC was full of oil, especially if the engine has ever been over-filled at all.

The simplest method for avoiding the recurrence of this problem is to disconnect the PCV hose at the valve and plug it with a bolt and a hose clamp. Then run a length of 3/4" heater hose from the valve down to the lower engine cover, avoiding any moving parts. That's all you really need. Some folks like to add an air filter or a "catch can" to the end of the hose. Others are trying to figure out a way to remove the vapor from the crankcase gases with some kind of inline trap and return the "clean" gases to the PCV inlet. I just stuck the hose on there and forgot about it. After 25,000 miles the only problem is a bit of an oily stain on the upper side of the belly pan. Other than that, no trouble at all. I haven't checked lately to see if there's still oil in the intake, but I'm sure some residual stuff is still making it's way to the intercooler. I'm going to give it another good cleaning in the spring just to make sure.

-mickey

My TDI uses Mickey's setup for the PCV modification. I went one step further and added a $1.99 Purolator PCV Breather Filter from Pep Boys to the end of the hose and plan to replace it with $.99 refills every couple of years.

Once in a while, the engine will suck in some air through this hose (don't know how often or how much) and I didn't want unfiltered air/dust getting into the engine.

The Breather Filter's I.D. is also 3/4" and it attaches to the hose with a clamp, - measures approximately 1 1/4" X 3".

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2000 Jetta GLS 5-speed: Silver / Gray

Do you guys take off the hose before bringing in your car for service?

Intercooler cleaning is a hoax.

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Ric Woodruff

Braumeister von Sehr Guter Bier
Since the Last Millenium

Oh, I get it. Ric has been stealing Dparnell's nasty pills!

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Always interested in steep & deep.
Just wishing for the deep part right now!!!

Ric, Changing your oil is a hoax too.. just use a good filter and add a little Quaker State 10w40 every now and then. You'll be fine

Ric,

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Intercooler cleaning is a hoax.<HR></BLOCKQUOTE>

I don't get it. Surely you didn't blatantly contradict the idea of cleaning an intercooler just for the sake of going against the grain (like always). I'm sure you're really giving us a legitimate warning about a hoax. You mean when one cleans his/her intercooler, it's not REALLY clean? Although that 1/4-cup of oil spilled out of Stinky's IC, it's really still in there? Isn't that what a hoax is? Something that isn't real?

Watch out, guys! You're not really cleaning anything!

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Scott Farrell, KE4WMF
98 Jetta TDI w/60,000 mi
Best Tank: 802-mi/55-mpg US

Scott's Jetta TDI Page
(Features TDI Articles, Sound
Files, and Spreadsheet)

[This message has been edited by Stealth TDI (edited February 06, 2000).]

Now, now, guys. For Ric, who shifts at 1800 rpm and doesn't really care about how his car performs, it really isn't necessary to clean the intercooler. Driving slowly might make the intercooler stay clean for a long time, and the car will continue to operate with a filthy intercooler. But if you're like me, and mash the pedal to the metal on a regular basis, the car will make the intercooler dirty, and this will cause a loss of performance. I know, because I did some testing before and after, and I know that a lot of gunk came out of my intercooler.

Both sides, lay off, before this gets out of hand and I have to start deleting posts. Ric, before making blanket statements like that, please explain your reasoning, and recognize that not everyone drives like you do.

Brian P.
'96 Passat TDI

[This message has been edited by GoFaster (edited February 06, 2000).]

Thank you, GoFaster. When new members to the forum post legitimate questions, and you het replies like these, it makes a potentially worthwile forum confusing and useless. Please provide honest responses!

What I mean is that 1/4 cup of oil at the bottom of the intercooler has NO effect where it counts; on thermal transfer at the intercooler tubes.

Yes, if those tubes are actually caked with thick crud, thermal transfer would definitely be reduced. Has anyone actually seen such caking of crud?

It probably makes sense to at least remove the part once in a while and get rid of the oil.

The good part of a bypass is that if the crankcase is overfilled oil won't overflow into the intake via the pcv route. Of course this is a Catch-22: if you do the oil change yourself, you won't overfill it and if the dealer does it, you might remove the pcv bypass.

Ric, it's impossible to see inside the intercooler, but if there's gunk in the bottom there will be gunk throughout. I did some timed acceleration tests way back when I first did the job, and there was a noticeable difference, which became more pronounced with repeated acceleration runs (i.e. intercooler was heating up and not getting rid of the heat).

Another unscientific indication: Before, if I drove around for a bit with the foot to the floor, then stopped and felt both intercooler tubes, they would both be warm. Now, if I do the same thing, the one going to the intercooler is warm, and the one coming back is MUCH closer to the ambient temperature. Unfortunately I don't have instruments to measure temp's in and out ... that would be the best indication!

Brian P.
'96 Passat TDI

Brian, don't forget that Ric does not drive with his foot to the floor.

GoFaster:

What do you mean you can't see inside the intercooler? All I had to do is remove my battery, and then remove the tube at the top. You can then see clearly right into the intercooler with a flashlight and look at all the heat transfer tubes.

At 40,000 miles, mine was bright shiney metal, with no trace of dirt or gunk.

BTW: The weather might have been a lot cooler when you checked the in/out intercooler tubes after you cleaned the intercooler vs. before the cleaning, allowing you to draw a false conclusion.

There is no oil sump at the bottom of the intercooler, Ric. If 1/4 cup drained out of it, you can assume that the thing was thoroughly plugged up. Besides, in my experience the stuff in the IC is quite viscous and won't drain down the the bottom entirely, even if there were someplace for it to go.

And what exactly do you mean by "hoax?" Are you saying that oil does not get into intercoolers? Are you saying that the IC transfers heat just as efficiently with an internal coating of oil? Or are you saying that we're lying when we claim to have cleaned the intercoolers? Any of the above would be completely wrong. You have absolutely no personal experience or data to back up your claim. You're arguing against personal experience AND common sense.

For the millionth time: If you have a contrasting point of view, with a meaningful argument to back it up, feel free to post it. Otherwise, please keep your juvenile crap to yourself.

-mickey

Does the positioning of the IC have to do with the collection of oil?

Does Ric's IC have the hoses going in and out in a vertical position?
Are Stinky's hoses going in and out horizontally?

I know the set up is slightly different from model to model and depending on body type (A3 vs A4).

Has anyone doen the cleaning on a 99.5 or 00 Golf TDI?

Plain and simple is don't pay attention to whatever Ric thinks he knows, because he doesn't know and you DO NOT want to know what it is that he DOES NOT know! Just filter it out and go about your business with your VW TDI.

Ric, your info sux more than my turbocharger!

Yes, my intercooler flow is vertical; one hose out the top, and the other out the bottom in my '98 Jetta.

BTW Mickey: "Thouroughly plugged up" would mean NO air gets to the engine and engine runs NO more. Even if a major quantity of oil somehow got into the intercooler, doesn't it make sense that the high velocity air thru the intercooler would simply blow the oil right thru the system for the engine to burn?

Well, lets put some more diesel on the fire. I have been attempting to put my tuning box on my 99.5 Jetta. I had to remove the boost sensor during this try. It is above the IC. There is oil dripping from it! Sure makes me want to clean it!

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99.5 Jetta GLS Silver Arrow
Tuningbox received! Now need to install it...

Ric: not on my car, with the Passat there is no way to look inside the intercooler without a LOT of work.

The acceleration testing before / after were done within about an hour of each other, the length of time it took me to do the job!!! Temperature and conditions were practically the same.

Brian

Karl: I have not yet gone in for service. I plan to keep the PCV mod. I do not believe it effects emissions. The worst thing they can do is reverse it. Then I'll spend another $5 on parts and do it again.

How much gain are we talking about? I have never even considered cleaning the intercooler to gain some lost power..... I might do it to see who's opinion I'll back up: the pro-gang or Ric (he seems to be alone). Gimme a couple of days.

in Ric's case he is right. the oil will stay completely out of his intercooler.

It should however create a nice swimming pool of oil at the low point of the bottom hose. At some point, maybe not for another 100,000 miles, the air flow will be restricted or the oil will start to be blown all over the place inside the cooler, which would be worse than having it pool on the bottom of the cooler.

Ric isn't wrong in this case, it is just that he hasn't prefaced his opinion with the facts of his situation. As with just about every other one of his opinions he is correct in such a limited sitiation that it is actually incorrect for nearly everyone else. SO Ric, work on the preface of your opinions. . . 'kay? A couple words before will save pages and pages of discussion.

The crap in the intercooler isn't oil, it is sludge, the crap that comes out of your PCV valve and is terminal to everything it comes in contact with. Only a fool wouldn't keep his intercooler clean from sludge.

Motor oil is viscous. The gunk in the intercooler is considerably more viscous and sticky than the stuff in the crankcase. It will not magically "drain out" no matter how the inlet and outlet is arranged. There will always be a layer of gunk in there insulating the intercooler unless you clean it out. If you never push the engine hard enough to make the IC relavent, then don't worry about it. But bear in mind that the intercooler contributes to efficiency in general, which translates to both power and economy. A good example is the Ford Powerstroke engine. A large intercooler was added in 1999 models. Both power AND fuel economy were improved by that simple addition. The less efficient the IC, the lower your fuel economy will be. And that doesn't even account for the physical obstruction that a lot of gunk can cause. I'm just talking about heat transfer.

Clean your intercooler once in a while. It's cheap, it's easy, and it's worthwhile.

-mickey

I still haven't heard anyone stating how much gain we are talking about here......

I noticed a slight increase in power available during hard driving after I cleaned my intercooler at about 15,000 miles. If you drive gently and never get into the boost it shouldn't matter much, as long as the oil and sludge doesn't get so thick that it physically obstructs the airflow. Most of the time there is little or no positive boost pressure, so intercooling isn't relavent. At first this will be a "high performance" issue. It'll become an everyday performance and economy issue later, but not until you have quite a few miles on the vehicle. (80,000???)

-mickey

-mickey

The difference is most noticeable under conditions where the engine runs under load for a period of time. When I did it, I did repeated timed acceleration runs from 100 to 120 km/h. With a clean vs dirty intercooler, there was little or no difference on the first run, some improvement on the second run, and a much more pronounced improvement on the third run.

In other words, it's most noticeable under conditions like hill climbing or trailer towing. I tow a trailer with my car, and under those conditions it needs every bit of power that can be found.

I figure that when the car is moving but not really under load, the intercooler cools down, gunk and all, and it takes a while for it to heat up. If you then put the engine under load, if the intercooler is dirty, it heats up and can't get rid of the heat fast enough, whereas if it's clean, the heat gets transferred out right away.

Brian P.
'96 Passat TDI