Question about Caterpillar Cat Pump Pressure Washer Pump 3SP30G11

Open Question

I have an excel pressure washer 11 hp Honda engine. water is leaking into the cat pump 4hp40gl causing the oil to become milky, after the washer sits overnight the oil clears up. Any and all help will be appreciated. Thanks

Posted by Anonymous on


6 Suggested Answers

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.

Posted on Jan 02, 2017

  • 1 Answer

SOURCE: I'm working on a 3126 cat engine. Problem oil in

Sounds like high pressure oil used to actuate the injectors is bypassing one or more injectors internally. There was an issue with this on engines with 7AS / 8YL serial number prefixes. There is no real way of isolating the problem, so the fix would be to replace all six injectors.

Posted on Jul 18, 2009

  • 4090 Answers

SOURCE: 11 HP Honda engine won't start.

Ypu could try a canned spray called AERO START which is a chloriform based accelerant. Spray into air intake and start engine. If it doesnt start with this solution then there is a serious problem.

Ensure the spark plug is actually sparking .
Remove it from the socket and place near an earthpoint while still connected and turn motor over. If it sparks then tick that box.
Ensure the spark is strong rub sand paper over the element of the plug to make it bright and shiny

check the lead is in good condition replace if nescessary. A bad lead especially carbon fibre crack inside and become leaky causing poor spark or no spark. If this appears OK then tick that box!

Place a spray of Aerostart inside cylinder and replace plug start engine again. if it fails to respond it will need to be seen by a mechanic

Posted on Jul 22, 2009

  • 68 Answers

SOURCE: cat pressure washer pump model 4hp40g1 no pressure

Sounds like you may need to remove the valves to check for any dirt etc. Is the machine juddering when on pressure. If so then it will be the valves that just want removing and cleaning

Posted on Jun 16, 2010

  • 2 Answers

SOURCE: Ex-Cell EXPRO2530 w/Cat Pump. Pressure builds and stalls engine.

Your unloader valve is not wotking, get a diagram of the pump from cat and it will show what parts you need to replace, or check for blockage in the valve.

Posted on Jan 10, 2011

  • 2 Answers

SOURCE: I have got a Devap

yes pump can be taken apart but when you do it will be to your best interest to rebuild with new valves and o rings. Be sure to check the housing and make sure it isn't cracked. If it is cracked throw it away and get a new pump.

Posted on Sep 20, 2012

Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

No pressure so removed pump. What is milky yellow substance leaking from openings in engine and pump when I pulled pump off?

Hi Dawn:
Milky coloured substance is usually a mixture of oil and water.
I would be checking for a bad pump shaft seal that is allowing water to get from the pump into the engine crankcase.
This is something that needs to be resolved before engine damage results.

Apr 22, 2016 | Garden

1 Answer

Oil is milky colored on my kingcraft pressure

Milky-looking oil is a sign of water mixed-in with the oil. This is often a sign of severe engine damage (cracked block, cracked head) in a water-cooled engine. (i.e., one having internal water jackets such as a car engine). On a pressure washer it is sometimes an indication that the owner used the pressure washer on itself, i.e., so as to clean the pressure washer with the pressure washer - very bad idea. If this is the case, then the pressure washer is most likely ruined. In any case the milky-looking oil is a sign that the oil has become contaminated with water, and probably a lot of water. I would drain the oil completely and replace the oil filter too if it has one, then refill the crankcase with new oil. Then try using it again for 10 or 15 minutes or so, then reinspect the oil. If it's milky-looking again then I'd set it out at the curb on trash day.

Oct 20, 2014 | Garden

1 Answer

G2500vh engine problems

Hi Derek.
It is almost impossible for the engine oil to become "milky" under normal circumstances. If you have changed the oil and have used the wrong type, it may become aerated and appear milky. The only other way for water to be added to the sump is through the oil filler. I doubt this is the case as it is a neglect thing and indicates that someone has run the machine without the oil filler caps. Hopefully this is not the case, but as the engine has a low oil level sensor, it might be the reason why it wont start. It's a safety device.
There is no way that the engine oil can be contaminated by water from the pressure pump.
If you mean that the water pump oil is milky, this means that the seals have failed between the pump and the transmission. Difficult to check in a G2500. If this is the case the machine has probably been used beyond the manufacturer's intent and has overheated.

Nov 12, 2013 | Karcher Garden

1 Answer

The pump is leaking some gray fluid

Gray fluid is usually indicative of old oil with water mixed into it. First you have to determine if the fluid is coming out of the motor or pressure pump. Then change the oil in that, or both, and then watch the condition of the oil when you use the washer. With new oil, it won't turn gray but will get a milky coloration to it. There shouldn't be any way for water to get into the motor oil short of the engine being sprayed directly with high pressure water. If water is getting into the pump oil you'll have to check the seals inside the pump.

Feb 14, 2013 | Honda 5hp 5 Hp Engine Motor Xr2500 Xr 2600...

1 Answer

Oil milky white in pump

it may have a slow water leak inside the pump.
change oil and monitor the new oil.
if it goes milky the next time you use it then it has a bad leak and the seals will need to be
replaced,otherwise the bearings will rust & seize

Dec 18, 2010 | Honda Pressure Washer PSI 3000

1 Answer

Milky oil leaking from left side caseing?

If water gets inside the gearbox, it will emulsify due to the "blending" caused by the gears and crankshaft. It turns the oil a milky color. The water can come from a bad oil seal on the water pump (if the bike is water cooled), or from condensation inside the gearbox. Sitting out in the rain, pressure washing or riding in creek beds can also be the water source. Find the water source and fix the seal or otherwise remedy the exposure. You will need to do an oil change. Please rate my answer. Thanks.

Sep 13, 2010 | Honda NSR 125 R Motorcycles

1 Answer

What type of oil can i use

The engine and the pump can use the same oil. SAE 30 non detergent oil. No need to pay more for speciality oil. Check oil often and look for any unusual signs such as milky or foamy oil in pump which would indicate water leaking past seals. Good luck.

Sep 04, 2010 | Honda Black Max 3000 Psi Pressure Washer

1 Answer

Honda Excell 2600 no pressure and water is leaking from the pump. i believe it's the unloader but can i fix it myself. i'm handy with tools and repairs but do no have the manual.

a manual will not tell you how to replace the unloader if you have the same unloader you will need a pressure gauge to adjust it at 2600 psi and your spike pressure should not exceed 3100psi and the leak at pump you need to check your oil make sure is not milky and if not you will need seals also

Aug 23, 2010 | Garden

1 Answer

Got a Dewalt 3800 PSI Pressure Washer with 4.0 GPM with a Honda GX 390 gas engine. Tipped it up to roll it out to my truck and got a big puddle of water with what looked like Pump oil in the puddle. Can...

Could very well be. Did you check the oil level and condition of oil? If its too full or if its light brown milky, then water has entered crankcase. Pressure washer pumps cannot stand to ever let run dry. Even a little. Also excessive idling will overheat pump if it doesn't have a thermostatic relief valve that allows some more cool water to enter pump.If it doesn't have one add one. Find your PUMP mfg and model number. IF it's pumping good now and no leaks, quick replacing the seals will save big future repairs. has lots of info on many pump manufactures. Or get some seals from dewalt.

Aug 11, 2010 | Dewalt 3800 PSI Pressure Washer

Not finding what you are looking for?

Open Questions:

See all Caterpillar Cat Pump Pressure Washer Pump 3SP30G11 Questions

Caterpillar Cat Pump Pressure Washer Pump 3SP30G11 Logo

Related Topics:

37 people viewed this question

Ask a Question

Usually answered in minutes!

Top Caterpillar Garden Experts

J.D. Browning
J.D. Browning

Level 3 Expert

2760 Answers


Level 3 Expert

400 Answers

Bill Boyd

Level 3 Expert

42725 Answers

Are you a Caterpillar Garden Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides