Problem with a Cat 3306 in a 980B loader

[oarwhat]

Hi All a newbie to this forum . I have a 980b that last year, leaked antifreeze from the orings on the precombustion chambers. I replaced them but now one year later they are leaking again. I used Cat orings these are red in color. The orings are turning soft and falling apart. Does anyone have experience with this?? No problems in 10 years before this. Thanks Randy

 

[LonestarCobra]

What did you lube the seal with when you installed them? Depending on what you used, the lubricant can deterierate the seal.

 

[Cmark]

Which seals did you use? The 7S3206 seals in the parts book changed to an improved 6v1585.

Also as lonestarcobra said, lubricate them with soap and not oil.

 

[oarwhat]

Thanks for the quick replies!!!! This site is great I just wish I asked this question before I replaced the orings.:Banghead I used the old style oring 7S-3206 and I lubed it with soap. I'm wondering if I have a slight leak at the valve cover allowing oil to fill the cavity above the oring. Or when I bled the injectors the diesel ate them up. I can't believe they use orings that are affected by oil. Are the new improved orings also affected by oil??? I'm surprised my Cat dealer didn't supercede it to the new oring. It might be because I gave them the number instead of making them look it up. I've had allot of problems with parts since they built the new super dealership. Thanks Again!!! Randy

 

[Cmark]

According to the service magazine, "The new seal is made of a material which has more resistance to heat and steam than the former seal"

Don't be too hard on your parts guys. This sort of thing does normally update automaticaly when the old number is put into the parts system. In this case, it doesn't. I had to do a little digging in NPR. Also, the magazine only applies the new seal to;

518 ( 50S, 55U ) Skidders;
955L ( 85J, 13X ) Loaders;
950 ( 81J ) Loaders;
130G ( 74V, 89Y ),
120G ( 87V ) Motor Graders

but I don't see any reason why you can't use it in any 3300 PC engine.

We are also told "Do not use the new 6V1585 Seal in engines that have the precombustion chambers installed under the valve cover", implying that the new seals are not resistant to oil.

I'm afraid I have to disagree with you that the O Rings should be resistant to oil. If the application calls for sealing coolant against atmosphere, why use oil resistant material? If it leaks oil, fix it. If it needs bleeding, clean up the spilt fuel. BTW, this isn't intended as a personal criticism, just a guess at the way the way the designer's mind works.

Next time you are at the dealership, ask them so show you SEBD1929 and you can see the info first-hand.

 

[oarwhat]

CMark Thanks again for your help. I was alittle frustrated yesterday didn't mean to pick on the parts guy's that much. I just wish I knew last year the orings were sensitive to oil and diesel contamination. I might have a small leak at the valve cover but I bet the diesel from bleeding did the damage. I'll keep an eye on the leaks in that area now. Randy

 

[Cmark]

If you're thinking about fixing your oil leak, you may also want to know that there is an updated valve cover gasket available. It's made of rubber is is much better than the cork gasket. The new part number is 1331247.

There are also some washers to be changed and a different tourque setting. Ask them to print out SEPD0418 for you.

Good luck.

 

[John C.]

I've put dozens of those engines together and never had a problem with the O rings. I would be suspicious of something else being wrong. Cracked precup or head, electrolysis or something else.

Was the copper gasket on the precup replaced on the first change?

 

[oarwhat]

John C. the gasket at the base of the pre cup was changed but it's steel not copper. I don't think the head is cracked never had white smoke. I filled the radiator to the top and no bubbles. Also no bubbles around the pre cups. Randy

 

[John C.]

What about the area the O rings contacts. Was the surface worn. How many hours on this engine?

The oil thing just does not make sense if there was no oil on it when you installed the precup. Now days you will be hard pressed to find one of those engines that doesn't have valve cover leaks.

 

[oarwhat]

Hi John I agree it doesn't make sense but, I think these rings are made for very high temp and that's why they're oil sensitive. I thought maybe they melted from the heat of the turbo so I put a propane torch to an old one. It turned red hot but didn't burn up. I just replaced these last december and they look 20 years old. They turned soft and are cracked etc. It might have a small leak but it's not runing down the side of the engine and driping on the ground. It's an old snowplow loader, don't know the hours but the engine is tight with good compression and little blowby.

 

[tctractors]

3306 motor.

If I had to put this small problem right, I would strip off the Cooler cores and also check the water pump and radiator, the pump for any impeller fault, the radiator for pegging up with trash/dust, but I will ley money down that the cooler/s are blocked up fairly bad and need poking out with a piece of wire or welding rod, this always causes the chamber seals to fail, they will crumble to bits as you try to get them out of the chamber groove, a common sign of getting to hot or low water movement, I always keep at least 2 sets of chamber seals handy plus the cooler (gasket) kits, if you run the engine for say 2 hours then turn it off, if you hear water gurgell or odd noises from the engine, the coolers are blocked, always strip them down totaly to clean them.

tctractors

 

[oarwhat]

TC Tractors I think you hit the nail on the head!!!!!! My orings are just like you said stuck in the grooves and falling apart. I've been chasing a flow problem for a while. Never enough heat in the cab even though the engine ran a little warmer than my other machine. I've flushed the radiator, put a new impeller in the water pump, moved the heater hoses around to find more flow, repaired the fan shroud for more air flow through the fins. I finally put a 12 volt water pump to pump warm coolant to the heaters. BUT I NEVER THOUGHT ABOUT THE COOLERS!!!!!!!! I bet they are totaly clogged. MAN I LOVE THIS WEBSITE

 

[oarwhat]

plugged cooler

TCTractor you are the man!!!! :notworthy My cooler was plugged about 90% . I have no idea how my engine kept cool at all. I have a picture and will post when I have a minute. Thanks Again Randy

 

[oarwhat]

plugged cooler

double post

 

[hartzou]

The best way is to contact your Cat supplier

 

[BIG D]

prechamber seals

I agree you have a flow problem probably coolers . Just food for thought but flushing a severly dirty cooling system bteaks large debree loose and actually makes the cooling ptoblem worse I have seen customers try flushing cooling system plug the top of the rad with debree mostly plain rust and junk thanks The BIG D

 

[oarwhat]

it's overheating again

Well even with the blocked oil cooler cleaned it's overheating again. The isn't any other coolers besides the oil cooler is there? Any ideas to check where my flow problem is? Thanks Randy