Cat 3406B water in oil
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Tom

Galien, MI

#1 Dec 13, 2008
Just recently purchased a truck with a 3406 B cat motor. Runs great (no load) Bobtailed home about 150 miles no problems. Changed oil, filters, etc. and added 3 gallons of coolant to radiator. Oil was black (normal looking without signs of foam or milkey look). Warmed up and moved out of shop. A few days later warmed up and brought back in shop to work on wet kit. Noticed oil level up about 2 gallons and very milky. Radiator again down 3 gallons. Added coolant, warmed up again and put overflow pipe in bottle of water to look for bubbles of coolant. None came into the bottle. Opened up radiator cap and observed no bubbles. Drained oil, removed oil pan,pump,shim plate. Pressurized radiator through water filter hose and let run with radiator cap venting air out of overflow tube. Observed all cylinders and no sign of coolant dripping. Plugged hose with finger to increase pressure to app. 25psi? and still no sign of coolant. Does anybody know what else I can check before I pull the heads? If it is a cracked head gasket and not bad o rings or cylinder dropping wouldn't I still get coolant coming down one of the cylinders? Maybe I need more pressure but I don't want to damaged radiator. I also checked the drain hole in the water pump, pulled out foam plug and no sign of coolant there.??????

Since: Jul 08

Location hidden

#2 Dec 14, 2008
then theres only two options. either you have a cracked cyl head or a blown head gasket/water seals. remember that a cracked head usually leaks only when hot. you wouldnt happen to have a water cooled turbo on it?
Tom

Galien, MI

#3 Dec 14, 2008
no, its an air cooled turbo. Only other source is air compressor. I have heard of two other trucks that the problem was the water pump seal. They said that the water pump is designed to pull oil back toward the engine by way of a spiral groove and the water will not necessarily leak out the weep hole but will be pulled into the engine. The fact that I did not get any water in the oil when the radiator was 3 gallons low on a 200 mile trip, and then only running at idle for about 15 minutes after I changed the the oil and added three gallons of coolant to the radiator. To suck three gallons of water into a lukewarm engine at idle I cannot think of anywhere else this could occur. Unless there is a huge crack in the head, gasket, orings, etc. which I am sure would easily been detected with the compressed cooling system. Please let me know what you think of this theory. Thanks, Tom
Tom

Galien, MI

#4 Dec 14, 2008
I was just looking at the motor again and noticed that the top three gallons in the radiator is about that much higher than the return line from the pump. Could this head of water on the back side of the pump have anything to do with the water entering the oil through the pump and only entering the engine when the level in the radiator is that high? Tom
Tom

Portland, MI

#5 Dec 15, 2008
Finally after being under pressure the cylinders started dripping coolant at the bottom of the sleeves. I will pull the head and sleeves and put new packing on all cylinder liners.
will

Guyton, GA

#6 Jan 16, 2011
i have a 3406 400b cat just been inframed 10000 miles ago i have water coming out of overflow tube on rad i loose about 1 and a half gallons of water a day put new rad cap on but still does it what could be the problem?

Since: Dec 11

Thompsons Station, TN

#7 Dec 10, 2011
I have an 87 3406B in a W900 KW and replaced all the o rings on the oil cooler and now its leaking water/antifreeze from a plastic plug looking deal that you can stick an allen wrench into. What is the purpose of this plug hell it you can see daylight through it did not know if you are supposed to be able to see through it or not?

Since: Dec 11

Thompsons Station, TN

#8 Dec 10, 2011
And what can I do to correct this water/ antifreeze from leaking out of this cheap plastic plug? It does have a rubber seal behind it btw.
faisal khan

Abu Dhabi, UAE

#9 Apr 20, 2012
hi to all of u , ihave someproblems in my catterpillar engine ,model 3306B, the engine oil is comming in to water radiator line , kindly give me the rerason for this fault , so i can fix it , my frnds am waiting for ur answer .or u can kindly give me a single miss call i call back you at the moment ,+971552080387.

thanking you
faisal khan.
chris

Sugar Land, TX

#10 May 14, 2012
possible your oil cooler is faulty causing the higher pressure oil to enter the cooling system
chris

Sugar Land, TX

#11 May 14, 2012
at Will. you need to check to see if your getting air bubbles in the radiator if so possible head gasket failure
Anonymous

Male, Maldives

#12 Sep 18, 2012
pls answer me, my F996 cat loaders 3306 TA engines cooling water getting into the engine oil sump, this happen after i have renewed water pump but no water found through pumps peep hole, tell me is this a problem from water pp??

“Cat & Cummins ECM programs”

Since: Jun 12

Marion, IN

#13 Sep 19, 2012
afrah_1977 wrote:
pls answer me, my F996 cat loaders 3306 TA engines cooling water getting into the engine oil sump, this happen after i have renewed water pump but no water found through pumps peep hole, tell me is this a problem from water pp??
You won't see water in the "weep hole" unless the front seal inside the water pump fails.

Before you changed the pump, did the engine get hot & overheat? If so, the head gasket most likely has "failed", allowing water to get into the oil.
Precisiongradewo rks

Franklin, TN

#14 Sep 24, 2012
What would cause water/antifreeze to come out of the plastic plug/screw on passenger side of engine near water pump. It looks like it takes an allen wrench and mayber a 3/4 inch wrench to tighten it up and has a rubber washer between it and the block. Im just wondering how to fix this for once and all.
Ken

Marion, IN

#15 Sep 26, 2012
Precisiongradeworks wrote:
What would cause water/antifreeze to come out of the plastic plug/screw on passenger side of engine near water pump. It looks like it takes an allen wrench and mayber a 3/4 inch wrench to tighten it up and has a rubber washer between it and the block. Im just wondering how to fix this for once and all.
Cat sells a brass replacement kit, complete with o-ring, for this plug. You can probably get it a KW or Pete dealer also, they stock Cat parts!
average

Tyler, TX

#16 Oct 13, 2012
I have a 3406b water cooled engine, when cold coolant is dark green and when hot is a bright green. The level isnt noticably low cold and not low when hot. The oil is jet black and lightly gritty when engine is cold once warm its a light greyish almost transpaernt and oil stick is gritty and bubbly. Nothing is overheating as far as the gauges go, given they are hooked up properly...any an all help is appreciated...

“Cat & Cummins ECM programs”

Since: Jun 12

Marion, IN

#17 Oct 16, 2012
average wrote:
I have a 3406b water cooled engine, when cold coolant is dark green and when hot is a bright green. The level isnt noticably low cold and not low when hot. The oil is jet black and lightly gritty when engine is cold once warm its a light greyish almost transpaernt and oil stick is gritty and bubbly. Nothing is overheating as far as the gauges go, given they are hooked up properly...any an all help is appreciated...
These are the "warning signs" that your coolant & oil are mixing together. Could be caused by many different things, but it's only going to get worse the more it runs :(
roger

Severn, Canada

#18 Jan 23, 2013
loseing coolent not in oil or out stack pureser tested an holding would it be the injecter cups

“Cat & Cummins ECM programs”

Since: Jun 12

Marion, IN

#19 Jan 25, 2013
roger wrote:
loseing coolent not in oil or out stack pureser tested an holding would it be the injecter cups
If the pressure test was at least 20 psi and there's no "drop-off" in this pressure (assuming it was left under pressure for 30 mins) then the system should be sealed. Have you replaced your radiator cap yet? When the spring inside the cap gets weak, it will allow coolant to "seep" past the cap and out the overflow drip tube to the ground while you are driving, even at lower pressure!

When the injector cup o-rings start to fail, you will notice "white smoke" coming from the exhaust stacks, since the coolant is flowing into that cylinder & getting burned-off with the fuel.
Dean

Melbourne, Australia

#20 Feb 9, 2013
Loosing water from radiator not going into sump can't find a leek where is water going to looses water hot and cold motor engine does not get hot

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