Fnic99

I would like to clean some of the grime and dust off my engine. In the past with other vehicles, I sprayed some degreaser on the engine, scrubbed a little, and washed it all off with a hose. I never had a problem. From reading other posts, it seems like other owners make a lot of effort to keep water out entirely. I don't want any problems so I haven't attempted this on the 928. Any tips to clean the engine compartment out? Can I take a hose to it safely?


Thanks

17prospective buyer

I would think you're safe with hose/household water pressure, i wouldn't use a power washer or any higher pressure to do the work. Scrub if needed then use water just to rinse off. One thing i hate is that the V of the engine has no drains, so if you ever spill oil down there or water, it's staying there and baking. Take a look at your ABS harness connectors/harness, it is likely falling apart or the insulation sheathing cracks when you touch it. A reason to not use any higher than line water pressure. Not only that but all the connectors are probably not water tight anymore like they were when new.

One good cleaner i've found that works fantastic for baked on grease/grime is diesel fuel, just fill up a spray bottle with diesel, spray, and scrub away. It won't eat anything or corrode like an alkaline or acidic degreaser will. Wipe off remaining excess with a rag, then use a solvent to dissolve the remaining oily film, such as Varsol, brake clean (acetone) etc or even just a light detergent like Sunlight.

MainePorsche

Absolutely.
See Stan's (MrMerlin's) recent post on his ISV dissection for one thing that can go south.

Fnic99

Thanks. I read his post a few days ago and decided to proceed with caution.

Fnic99

Thanks for the tips Matt.

Mrmerlin

after taking apart more than a few intake systems,
I would suggest to not use a hose rather a wet rag with car soap for painted surfaces.

NOTE use compressed air first to remove the dusty deposits stay away from electrical parts.

Brake cleaner can be used by spraying it on a rag then wiping down a surface ,
stay away from paint as it will remove it.

More than a few throw out bearings have been ruined with water that runs down the back of the block into the release arm opening then into the TOB and a few days later it is beginning to rattle.
Other issues like TPS or barn door modules failures or computer failures, possibly even green wire failures due to water /corrosion

I just dissected a Idle Control valve and it had rusted into a closed position this required a new part to be fitted and the intake to be removed.
I would advise against spraying chemicals as the gaskets and O rings may be damaged by these chemicals the damage wont be evident for a little while followed by oil leaks and vacuum leaks.

Of course you can clean things the way you want,
and some will tell you that this is how they do things for the last 20 years, YMMV

z driver 88t

There are probably more contrary opinions on this topic than any other on the forum I have run across. I do what I have done on all my cars for the past 25 years and after almost 5 years with the 928 it seems to work fine as well.

I use a mild degreaser. The one I like best is Autoglym Machine Clean - you have to track it down on line. It is citrus based with no petroleum products. I cover the distributor cap and the 14-pin connector with plastic shopping bags held on by rubber bands, spray down the whole engine, let it sit for a few minutes, brush what areas I can reach with an engine detailing brush, then spray it down with a garden hose using a strong spray nozzle to knock loose any built up oil and dirt. I don't spray electrical connections directly but I don't worry if they get a little wet. Let the hood stay open for an hour to dry then I take it for about a 15 minute drive to get the engine compartment good an warm to make sure everything is dry.

When it cools I spray down the whole engine bay with a protectant. I personally like Sonus Motor Kote which is a heat resistant, water resistant wax that works well for plastic and rubber, as well as cast aluminum.

I do all this probably twice a year and have been happy with the results.

123quattro

I drive the car to warm up the engine. Come home and spray the whole thing with Simple Green and then hose it off. I've been doing this with all eight of our cars and I've never had an issue with any of them as long as we've owned them. Engines get wet when you drive in the rain...

ThetaTau87

2nd on the Simple Green. I have not washed my 928 engine bay, but I've been using it for years to keep all my other cars looking great under the hood.

On my other cars I use a pressure washer, but it seems like the 928 is more susceptible to water intrusion issues on mechanical parts as well as electrical connectors/parts than my other cars. I'll stick with hose pressure.

davek9

+1 on this, and I'll add blow dry with compressed air and wipe down metal parts and spray electrical connections w/ WD40.

auzivision

Everything under hood was designed to withstand a splash of water, but that was 20+ years ago.

Rubber and plastic deteriorate over time. So it's really a matter of your risk tolerance and engine bay condition. For the most part, 'electrical' items are the most vulnerable, so easy does it around all wiring... which is almost everywhere.

Part of me thinks washing is good, because it can knock out weak links. Don't be surprised if you have to fix an item or two maybe more depending on how recently items have been refreshed. Like other said, YMMV.

Initial cleaning I used Gunk Engine clean gel and garden hose pressure to rinse. Once a certain level of clean is reached, it's much easier to maintain by spot cleaning with a rag. Also, anytime I have a part off that is even remotely dirty, I clean it real good before reinstalling.

auzivision

+1... and a leaf blower works pretty good too

Fnic99

Thanks for the advice everyone. I was looking at the thread below (great info btw) and really wanted to get the engine compartment as clean as possible to match the rest of the car. I may attempt to paint the intake and cam covers. Sick of looking at the flaking paint. Just need to get all the dirt and grime off first.

https://rennlist.com/forums/928-foru...finishing.html

worf928

+1,000,000 what Mrmerlin wrote.

I would add that a citrus based cleaner, brushes and elbow grease followed by a spray bottle rinse of distiller water is the way to go. Use brake clean on a brush or rag for stubborn spots. And keep the brake clean away from paint and intake/cam cover coatings and harnesses. Uncoated metal only.

There is no way - ever - I would consent to hosing down a 928 engine bay unless I knew for a fact that every connector and bit of rubber was in good shape (and in that case it probably wouldn't need to be cleaned...)

If you want a concurs engine bay and you now have a dirty, greasy engine bay with old sensors, cracked connector boots, etc., then disassembly is the place to start.

928Myles

My intake temperature sensor died almost immediately after washing the engine one day. I was told that it probably got water in it and that it shouldn't have been sprayed even with a low pressure hose.

I would err on the side of caution.

Myles