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Cleaning an engine

Hi all, I was wondering what are your thoughts on washing, cleaning your engine out yourself using a product such as Gunk engine cleaner. I’ve seen videos on YouTube of people cleaning their cars with no problems but I know the moment I try and do mine something will go wrong haha so maybe paying someone to do it would be better? . My engine is pretty dirty and I read a cleaner engine helps make things run at a cooler temperatures and is just better overall for an engine so I thought maybe this is something I could try and do.

I’ve washed many engines using Gunk and a high pressure washer.

Vehicles today have Weather Pack Connectors.

These pretty much make the electrical system water-proof.

And since there are no more distributors/carbs any more, it’s pretty hard to mess up.


Agree with @Tester, but a dirty engine does not run hotter. The cooling system keeps the engine temperature about the same regardless of the amount of grime on the outside. But it is easier to see leaks and such on a clean engine and a clean engine just makes the vehicle look like someone actually cared for it. I know that I’d be inclined to think that if the engine is clean, the vehicle was probably better maintained.

Tester I would trust you to pressure clean my engine compartment but I would not trust myself. I can see pointing the nozzle just where it should not be.

OP, why not get some estimates from detail places. It might not be as expensive as you think.
In the photo the battery and cables don’t look good.

I have never entertained the thought of washing an engine, Still scared from the olden days I suppose where moisture problems were more common imho.

Yeah I think I might do that. I’ll have to clean off the battery connectors while I check up on that

Yeah I’m with ya… I’m just too nervous about it myself.

Probably for another post but the check engine light tripped on today, engine was running pretty rough on the freeway… took it to auto zone to scan for codes and sure enough got a misfire on cylinder#1

Do not know the car or system but my first thought proper diagnosis for a proper repair. Ford 4.6 v8? what year?

The desert dust rinses off easy, I just spray it off with a hose once a year. While grease rinses away easier when the engine is hot you shouldn’t spray water on a hot engine. Avoid spraying water into the alternator or any other pulley with a bearing, especially if the engine is warm or hot. If a hot bearing is quenched with water is can draw water in and ruin the bearing.

Clean off that battery also, a clean battery will last longer and all that dirt will cause a slight discharge while parked.

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@Barkydog it’s a '98. And I think it’s coil on plug assortment so there are 8 coil boots & plugs you have to replace if you change them all out… which are fairly pricey for the pack of 8… I’m not sure how hard they would be to replace myself but at the mileage the cars at I’m pretty sure they’re getting close to all need replacing.

Not sure what is involved either, my car I bought used, wanted to do the plugs and could not even find them without disassembly. I think I have heard on this board you can swap the coil overs to another plug just to confirm, butt I am sure smarter people will chime in to help.

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That’s correct. mileage is at 240,000

Suppose with this being part of the Ford panther line of cars theres very knowledgeable posts and videos out there on repairing something like the sparkplugs

When I used my truck as a daily driver in Colorado I used to wash the engine at the local pressure-wand style of diy’er car wash. I’d wash it maybe a couple times a year. In those days it cost 25 cents for three minutes. I discovered by trial and error I had to cover the distributor and coil with some plastic first, and avoid spraying directly on the spark plug wires. I didn’t spray the alternator, seemed common-sense just to not spray it. Plus the alternator wasn’t the dirty part, on the 302 V8 it’s the valve covers and block and all the walls of the engine compartment that need some gunk removal rom time to time. I made sure to arrange it so I’d be driving the car for 5-10 miles afterward, so things would heat up & dry out. Never caused a problem that I know of.

I’m not so sanguine on the idea of washing the Corolla’s engine compartment like that. There’s so many electrical connectors that could get corroded. I did wash it that way a few times, but decided it wasn’t a good idea. The total electrical system in my Truck fits on 3 pages in the shop manual. On the Corolla, I think it is like 75-100 pages.

I agree.

Why take the chance of introducing water into electrical systems.

I am sure that car manufacturers design cars to handle normal dirt on the engine.

Have a good nite.


Cleaning an engine is fine. Use a garden sprayer on the shower setting so that you don’t force gunk into places you don’t want to force it. Use a good engine cleaner and some sort of semi-stiff-bristled agitator brush to get the stubborn stuff. Then wipe with a microfiber cloth.

Not a terrible idea to wrap suspect electronics like aftermarket alarm horns or stereo harnesses. First wrap them in saran-wrap, then wrap over the top of that with aluminum foil. The foil keeps the saran-wrap in place so it doesn’t get knocked off when you spray the water. If your car is older, do this to the distributor too.

That’s all fine.

But when a vehicle arrives on a roll-back, and the driver is pi$$ed because some hydraulic fluid is all over the bed?

Sometimes you need to pressure clean under the hood.


Don’t forget the shampoo and cream rinse.

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Don’t forget the shampoo and cream rinse.

Be nice.