Pressure Wash Engine Compartment 2006 Sierra 5.3

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I have always done a light pressure wash of the engine compartment about once per year on every vehicle I have ever owned just to take the dust etc. off. I just bought a 2006 Sierra 5.3L LM7 and there are a ton more electronic widgets on top of the engine (coils, wiring harnesses, etc.) than my previous truck (1996 Chevrolet K1500 5.7L). Is this no big deal to do a light spray (in soap mode then a rinse) under the hood? I have never covered alternators / distributors etc. with bags and have never had issues. I try and do it on a cool / warm engine (not hot). Good to go or bad idea?
 
Originally Posted By: marc1
I have always done a light pressure wash of the engine compartment about once per year on every vehicle I have ever owned just to take the dust etc. off. I just bought a 2006 Sierra 5.3L LM7 and there are a ton more electronic widgets on top of the engine (coils, wiring harnesses, etc.) than my previous truck (1996 Chevrolet K1500 5.7L). Is this no big deal to do a light spray (in soap mode then a rinse) under the hood? I have never covered alternators / distributors etc. with bags and have never had issues. I try and do it on a cool / warm engine (not hot). Good to go or bad idea?

Me too, never cover anything when I wash my LS400, E430 and S2000 engines and never had any problem. I use Castrol super-clean on warm engines with engine off, then use garden hose to rinse off with engine running. I use the shop-vac blower to dry the engine as much as I can, I then drive around few miles.
 
I've used a pressure washer a few times to clean up engines for friends, or for used cars I bought that I didn't maintain from day one. I just make sure I try and avoid connections and keep the pressure at a very low setting. It is best if possible not to let an engine get dirty enough to need a pressure washing.
 
Modern cars should be able to handle spraying down the engine w/ H20.

I would avoid using med-high pressure as that can get H20 into places it shouldnt be. Low pressure should be fine, but I prefer a simple rinse.

My method (2x/yr for past 4 years since new): Better safe than sorry, so I cover my alt, air intake and battery with Saran wrap. Use a spray bottle with very little (maybe a tsp to 32 ozs H20) Dawn dishwashing soap to saturate the compartment. Dont forget the underside of the hood. Use a garden hose to rinse. Finish off with a microfiber.

Sorry for the tight pic (was a DIY on another forum), but gives you a geneal idea how clean it is on my ride (notice the white engine cover):

PICT1411_0380paint.jpg
 
nice engine!! all my engines look the same way too!! i wash once a month and after i use 303 aerospace protectant to wipe down, the during week i use on my microfiber towel a bit of 303...so engine stay beautiful and protected.
 
I wash my engine 2 or 3 times a year. I never cover anything but I don't go crazy with a pressure washer either. I just soap it up by hand and rince with the garden hose. 2008 Volvo S40:
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Lately, I have just been using the high-pressure soap and high-pressure rinse options at the local coin-op car wash to pressure wash my engine compartment. I spray the compartment for 2-3 minutes continuously and have not had any issues.
 
I regularly clean my engine bay, but I would personally keep the pressure washer away. I use Simple Green diluted 20:1 by a hose end sprayer, hose it down with soap, use some kind of a soft, long-bristle cleaning brush if any areas need agitation, and then rinse with lots of low-pressure water.

If stubborn dirt is greasy, pressure won't help you - you need soap. If soap has loosened greasy dirt, then you don't need pressure to rinse it away. There are too many risks with high pressure water - not worth it IMO and simply not necessary unless you're trying to do a "quick" job on a neglected car that isn't yours (like a professional detailer).
 
In this order:

1. Saturate with simple green, purple power, or krud kutter in full strength.
2. Using a brush or multiple brushes, actually do the legwork yourself srubbing the grease and [censored] off.
3. Rinse with a garden hose.

Pressure will cause problems, however the less pressure of a garden hose seems to be less damaging. I see issues with col on plug modules (COPS) on newer cars. Water gets down in the sprakplug hose, and thus shorts out the coil.
 
Lots of people have reported problems after washing the engines on the GM 4.8, 5.3 an 6.0 engines. After repeated washings, the two knock sensors which are located on the engine valley under the intake plentum rust and cause issues. They sit in recesses which can fill with water because the rubber caps dont properly seal. That being said, I have washed the 5.3 several times before I found this out, without incident. I have since, stopped washing it, not wanting to take a chance.
 
Thanks for the information, Eric.

Is this with pressure washing? What's the consensus with rinsing with low-flow water?

I've been using low-flow water almost every month on my 4.8 since I purchased it. I dry everything the best I can with a towel and then run the engine to heat it up, but it makes me wonder if I should be checking into this.
 
Originally Posted By: bigmike
Thanks for the information, Eric.

Is this with pressure washing? What's the consensus with rinsing with low-flow water?

I've been using low-flow water almost every month on my 4.8 since I purchased it. I dry everything the best I can with a towel and then run the engine to heat it up, but it makes me wonder if I should be checking into this.


I have looked at the location of the knock sensors, any water flow (high or low pressure) can easly find its way under the plentum. I am just guessing that it somewhat depends on how well the rubber caps over the knock sensors seal on a paticular engine, as to how much damage is caused.
 
Apparently, it doesn't affect later version of the LS engine. Mine are located on the sides of the engine:

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0996b43f8020313a.gif
 
Here's the TSB:

1998-2002: Service Bulletin: Audible Spark Knock (Detonation), MIL Illuminated, DTC P0332 Set
Subject: Audible Spark Knock (Detonation), MIL Illuminated, DTC P0332 Set (Replace Rear Bank Knock Sensor and RTV Area Around Sensor)
Source: Chevrolet Dealer Technical Service Bulletin
Number: 02-06-04-023

Models: 1998-2002 Chevrolet Camaro, Corvette, 1998-2002 Pontiac Firebird
with 5.7L Engine (VIN G -- RPO LS1)

1999-2002 Chevrolet and GMC C/K Pickup and Utility Models (Avalanche, Silverado, Sierra, Tahoe, Suburban, Yukon, Yukon XL, Yukon Denali, Yukon Denali XL) with 4.8L, 5.3L or 6.0L Engine (VINs V, T, Z, N, U -- RPOs LR4, LM7, L59, LQ9, LQ4)

Condition:

Some customers may comment on a mild to severe engine ping (commonly referred to as spark knock), usually worse during acceleration and/or an illuminated MIL. Upon investigation, the technician may find DTC P0332 set.

Cause:

This condition may be the result of corrosion of the rear bank knock sensor due to water intrusion into the sensor cavity. This condition is more apparent on vehicles in which customers frequently wash the engine compartment.

Correction:

Replace the rear bank knock sensor and build a dam (wall) around the sensor using RTV to divert water away from the sensor. Use the procedure and part number listed below.

Remove the intake manifold. Refer to the Intake Manifold Replacement procedure in the Engine Controls sub-section of the appropriate Service Manual.

Remove the wiring harness assembly from the knock sensor.

Remove the rear bank knock sensor.

Install the new rear bank knock sensor. Tighten the knock sensor to 20 N·m(15 lb ft).

Install the wiring harness assembly to the knock sensor.

Apply a bead of RTV silicone sealant approximately 9 mm (3/8 in) wide and 6 mm (1/4 in) high along the outside edge of the ridge on the engine block valley cover around the rear bank knock sensor. DO NOT form a complete circle. Leave the rear section open as shown.

From the underside of the intake manifold, completely remove the rear intake manifold seal (foam material).

Install the intake manifold. Refer to the Intake Manifold Replacement procedure in the Engine Controls sub-section of the appropriate Service Manual.
 
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