I have a stock 1990 gmc c1500 5.7 engine it has gotten really dirty over the past few weeks and wanted to know how I’m able to clean such an on old engine bay or can I just spray it down?
Is it just dirty or is caked with grease?
If its just dirt, a trip to the car wash will do the job.
Put plastic bag around the distrubutor and around the throttle body and the alternator.
Bring your own degreaser. The car wash stuff is a rip off.
Dont blow any wiring off.
If it is a grease monster you need a different plan.
If it is just caked in deep built up dirt and oil.
Get under it and scrape as much of that crud as you can.
It is a dirty nasty job but it saves you in the long run.
Oil leaks mixed with dirt become a paste and the solvents evaporate out and turns into hard dried crud.
When you spray the average engine cleaner on that type of crud it melts the top layer for a bit but that crud pulls the solvents back into itself and only the top disolved layer washes off.
When you hit it with the water, whatever limited chemical reaction was happening stops.
Eventually you end up with re-occuring goo.
And a whole bunch of spray cans.
The zepp product is pretty good but I also really like "Keytone" from Lawson.
If you dont have access to those commercial products Easy Off oven cleaner will do the job.
But, you need to be very carefull with that stuff. It will melt the plastic and the rubber and take the paint right off.
And if you spray it in your eye you will likely loose that eye.
If have used the "Fume Free" oven cleaner on aluminum.
It isnt as effective but it does work and as long as you keep a close watch on it and rinse it off it doesnt etch the aluminun like regular Easy Off does.
If you do this, wear a face sheid and safety glasses and pay attention to the blowback when you hose it off.
Dont get under it untill it is bone dry and cant drip on you.