C4 (1987) Engine wash/degrease
Thread Starter
Intermediate
Joined: Sep 2024
Posts: 35
Likes: 4
From: Western MA
C4 (1987) Engine wash/degrease
I recently purchased a 1987 C4 and have been repairing all the little bugs I’ve read about. I have wanted to clean & degrease the engine, but I have read horror stories about owners who have either pressure washed or hosed down their engines, and have destroyed or shorted out modules under the hood.
I’m looking for some advice or guidance on how best to clean the engine bay, and what to watch out for. Also, I have typically used the Gunk or Carquest brand of degreaser, but would like to hear if there are other products out there that the group have used successfully.
Thank you!
I’m looking for some advice or guidance on how best to clean the engine bay, and what to watch out for. Also, I have typically used the Gunk or Carquest brand of degreaser, but would like to hear if there are other products out there that the group have used successfully.
Thank you!
Burning Brakes
Joined: Aug 2008
Posts: 866
Likes: 220
From: Tampa, FL
I recently purchased a 1987 C4 and have been repairing all the little bugs I’ve read about. I have wanted to clean & degrease the engine, but I have read horror stories about owners who have either pressure washed or hosed down their engines, and have destroyed or shorted out modules under the hood.
I’m looking for some advice or guidance on how best to clean the engine bay, and what to watch out for. Also, I have typically used the Gunk or Carquest brand of degreaser, but would like to hear if there are other products out there that the group have used successfully.
Thank you!
I’m looking for some advice or guidance on how best to clean the engine bay, and what to watch out for. Also, I have typically used the Gunk or Carquest brand of degreaser, but would like to hear if there are other products out there that the group have used successfully.
Thank you!
I used to be scared to hose down my engine, because I thought the same thing (shorting out modules, etc.). But I learned a few years ago that people actually put computer motherboards into dishwashers:
https://www.howtogeek.com/878176/you...ably-shouldnt/
It actually makes sense... the problem isn't the water, it's what happens if you start the car before the water completely dries. Your ECM is not weather protected, so it's likely stored inside the car somewhere (I don't know where). I know the later ECMs are located in the engine compartment above the battery, but for your year, the ECM is likely tucked away inside, I'm guessing behind the dash somewhere.
So if you have an MPFI system, the things you'd want to be concerned about are:
1 - Damaging or destroying the many plastic and rubber vacuum lines, which are likely dry-rotted at this point, and could break apart with solvents or high pressure water.
2 - Protecting the MAP sensor (which honestly I wouldn't be too concerned)
3 - Getting water into the intake (just keep it closed)
4 - Damaging paint on valve covers, etc.
5 - Getting water into the distributor.
Water likes to find its way into the distributor and can / will wreck havoc on the ignition control module. My biggest worry would be the vacuum lines, honestly. Otherwise, I see no issue with using a low-powered pressure washer.
Thread Starter
Intermediate
Joined: Sep 2024
Posts: 35
Likes: 4
From: Western MA
I used to be scared to hose down my engine, because I thought the same thing (shorting out modules, etc.). But I learned a few years ago that people actually put computer motherboards into dishwashers:
https://www.howtogeek.com/878176/you...ably-shouldnt/
It actually makes sense... the problem isn't the water, it's what happens if you start the car before the water completely dries. Your ECM is not weather protected, so it's likely stored inside the car somewhere (I don't know where). I know the later ECMs are located in the engine compartment above the battery, but for your year, the ECM is likely tucked away inside, I'm guessing behind the dash somewhere.
So if you have an MPFI system, the things you'd want to be concerned about are:
1 - Damaging or destroying the many plastic and rubber vacuum lines, which are likely dry-rotted at this point, and could break apart with solvents or high pressure water.
2 - Protecting the MAP sensor (which honestly I wouldn't be too concerned)
3 - Getting water into the intake (just keep it closed)
4 - Damaging paint on valve covers, etc.
5 - Getting water into the distributor.
Water likes to find its way into the distributor and can / will wreck havoc on the ignition control module. My biggest worry would be the vacuum lines, honestly. Otherwise, I see no issue with using a low-powered pressure washer.
https://www.howtogeek.com/878176/you...ably-shouldnt/
It actually makes sense... the problem isn't the water, it's what happens if you start the car before the water completely dries. Your ECM is not weather protected, so it's likely stored inside the car somewhere (I don't know where). I know the later ECMs are located in the engine compartment above the battery, but for your year, the ECM is likely tucked away inside, I'm guessing behind the dash somewhere.
So if you have an MPFI system, the things you'd want to be concerned about are:
1 - Damaging or destroying the many plastic and rubber vacuum lines, which are likely dry-rotted at this point, and could break apart with solvents or high pressure water.
2 - Protecting the MAP sensor (which honestly I wouldn't be too concerned)
3 - Getting water into the intake (just keep it closed)
4 - Damaging paint on valve covers, etc.
5 - Getting water into the distributor.
Water likes to find its way into the distributor and can / will wreck havoc on the ignition control module. My biggest worry would be the vacuum lines, honestly. Otherwise, I see no issue with using a low-powered pressure washer.
Dave
Burning Brakes
Joined: Aug 2008
Posts: 866
Likes: 220
From: Tampa, FL
