Pressure washing

#1

Years ago I was told to never pressure wash a diesel that is warm or hot. The person that told me this was a diesel injection mechanic with considerable experience. The reason he gave was that the IP housing would contract faster than the internals from the cooling of the water. He said this could cause clearance issues inside the pump. I have always heeded this advice, but it is not always convenient. Since I don't have a pressure washer, I have always had to drop the car off at the car wash and let it sit, returning later to do the washing. I like a clean engine bay, and I was just wondering if any one else had heard this. So, do you wash 'em hot or not?

#2

I wash mine warm. My DIY car wash is three blocks from work, so this works for me.

The advise you got is the same I've read, and it makes sense. I've washed them hot though, and let the temp equalize before starting. I am not worried so much about the housing shrinking and breaking something as I am about trying to make the pump do its thing with reduced clearances.

Spray it off, push it out of the bay (just good manners to let someone else be able to use it), wait ten. By then, the parts will all be the same temp again. Aluminum does not take long to equalize temp.

#3

I never wash engines hot, I always believe itll cause some kind of cracking or warping on the block. Or some bad stuff like exhaust manifold stud breakage, or stuff that wont exactly cost alot of money, but takes 18-20 hours of labor to fix.

But I prefer to wash them warm, 150-100 degrees, I find the dirt comes off a little eaiser, my pressure washer dosent really crank out alot of pressure.

#4

I own a pressure washer, but I don't use it for engine compartments -- I pay the money to clean them in someone else's yard!

I use my pressure washer for cleaning the moss off of stuff, mainly.

#5

asavage wrote:...I've washed them hot though, and let the temp equalize before starting...wait ten... By then, the parts will all be the same temp again. Aluminum does not take long to equalize temp.

Hmmm, I like that idea.

#6

Ten minutes is what I meant, just in case anybody thought I was implying that the IP housing temp and internals temp would equalize in ten seconds.

#7

asavage wrote:I own a pressure washer, but I don't use it for engine compartments -- I pay the money to clean them in someone else's yard!

My driveway is like a chameleon- it can change to all the colors of the rainbow when it rains

#8

I now have three reasonably clean engine compartments. I had dropped the habit of washing the engine bay for fear of damaging the IP. It was just too much of a PITA to leave the car sitting at the car wash as was my practice before this discussion.

Cleanliness is a good thing, but ignorance can be bliss too. It looks like two of my cars have a slow leak from the area where the vac pump supply line ties in to the block.

That repair will be coupled with intake cleanings whenever I track down the gaskets. I intend to have the manifold from my parts car cleaned and ready to swap in. This should split the project(s) up and keep the downtime to a minimum.

#9

goglio704 wrote:It looks like two of my cars have a slow leak from the area where the vac pump supply line ties in to the block.

My car has this leak also. Even thou I have cleaned and inspected several times it is impossible to detect where the leak is originating. There is no clear view sightline.

#10

You can see it from underneath to some extent. The steel line connects to the block with a banjo type fitting.

#11

Yes, and I was able to slightly tighten the banjo bolt; did not seem to have any effect in lessening the leak. Viewing from underneath still am not able to accurately pinpoint the source of the leaking oil.

#12

There are two banjo bolts. Three, if you count the one on the alternator.

I'm not sure how you get to the upper banjo. It might require removing the manifolds; I have not stuck my hand up in there.

#13

The upper one is where I have leaks. In my case, I don't intend to try anything until I pull the intake for cleaning.

#14

I don't think that you have access to the upper banjo fitting with only the intake manifold off.

#15

You may be right about that. The intake and exhaust manifolds are off my spare now anyway. I'll look into it and post some pics when time permits.

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Pressure washing

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