Degreaseing undercarige of Z

go7roo7

go7roo7

el pollo lento
Spectator
Hey guys, this weekend I swapped belts and did an oil change on the Z and I noticed a lot of old oil (+dirt) buildup in many areas underneath the Z. As far as I have owned the car I have not noticed any oil drips on the concrete while parked. I do know the engine was swapped by Nissan (by previous owner) due to oil consumption issues. I wanted to know if any of you know the best way to clean all that sludge off the bottom ( obviously with degreaser) so I can pin point a leak ( if there is). Should I take it to a car wash (with under cleaning) or just do it with a hose at home? ( I'm afraid of getting a sensor wet and causing damage so I assume the motor should be hot before washing the underside).

Thanks in advance.
 
Bro. The bottom of the car, gets super wet when it rains and your drive in it. Just hose it off. Also, if fluids aren't like puddling under the car, you'll NEVER find that leak.... Ever.
 
But that's the issue, it is pudding. I have no idea if this was like this from when the dealer swapped the motor. Sure as hell its been like this for a while since most of it is dry and sludgy.
 
But you said its not leaking onto the groud. That means like barely any is coming out. When oil and stuff like that gets slung around it makes it look about 85,000,000 times worse. Haha
 
yeah Its not leaking, but little bit of oil goes down from each oil change, I would rather have it clean(ish) so if there is a leak, I have a better chance of seeing it.
 
Jack up car, put on jackstands, spray degreaser, use high press hose/cheap low power pressure washer. Do it on a cold engine! NEVER spray cold water on/near a hot engine block. After spraying down with water let it sit and dry. You can help it out by using an air compressor and blowing air on sensors and what not. After its dry start engine and let it warm up, it will dry everything else that you cant see. Pretty easy stuff.
 
The carport/ car wash area in my complex is rather flat so I think I can use the ramps to lift the front of the car up enough to be able to spray all the bottom with degreaser then just wash it off with the hose. Thanks for the ideas guys!
 
JS said:
Jack up car, put on jackstands, spray degreaser, use high press hose/cheap low power pressure washer. Do it on a cold engine! NEVER spray cold water on/near a hot engine block. After spraying down with water let it sit and dry. You can help it out by using an air compressor and blowing air on sensors and what not. After its dry start engine and let it warm up, it will dry everything else that you cant see. Pretty easy stuff.
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Why wouldn't you do it on a hot motor ? I always wash my motor when it's hot so the water burns off fast and doesn't short anything . I did it cold once on the ka and the dizzy got wet and wouldn't crank had to wait about an hour for it to dry

And I always do it while to motor is running spraying degreaser all over and not spraying direct water to alt dizzy starter just misting it
 
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^ the same thing happened to my 02 Altima. Washed the motor and she did not start for 6 hours. And when she did, the idle was really rough. Most of the people have told me to do it with a warm engine and to not soak the motor with water ( so it doesn't cool rapidly and causes the metal to contract).

But since this is the bottom of the Z, I drive when its raining, soooo the bottom gets soaked anyway, I am just wetting the parts that are covered by the lower bars. Any sensor that is under the car should be more than capable of handling water.
 
Damian P said:
Why wouldn't you do it on a hot motor ? I always wash my motor when it's hot so the water burns off fast and doesn't short anything . I did it cold once on the ka and the dizzy got wet and wouldn't crank had to wait about an hour for it to dry

And I always do it while to motor is running spraying degreaser all over and not spraying direct water to alt dizzy starter just misting it
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Your crazy... Spraying cold water on a hot engine can crack your block and cause more damage than letting it sit and dry for a little bit. Oh and if your ever going to wash your actual engine bay and spray the top of your engine it would be a good idea to cover some of those things like the dizzy with a plastic bag as to not get it soaking wet. And again I would follow up with some help from the air compressor right after washing... Works for me.
 
Yeah water and hot is a no-no.

Now If you warm up the engine, and its warm to the touch, with all electronics covered, you should have no issue with cleaning it. Since, though we are mostly talking about the bottom part of the engine/ trans, I would think those components could be wet when hot, since when it rains, its soaked anyways.
 
When it rains your motor and block get wet . If you have freezing cold water then yea don't spray the block but normal hose is not "cold" enough to crack a block. Also if your motor is over heating then yea you shouldn't throw water on it . Only thing I don't throw water on directly is alternator starter dizzy and plastic radiators.
 
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