Leaking CAC

[Pete1990]

Little info here.
Was driving in Texas and heard a Pop and sounded like a CAC boot came off.. It went away after about 5 seconds of being off the throttled. Got home this weekend and tested the CAC its leaking not a LOT but its leaking. Leaks about 2-3 PSi in the matter of 1 min.
I've read that if its leaking at all its time to replace. Cummins says 5 PSI in 15 seconds.. Dealer wants $1600 for a new CAC and doesn't have one in stock. Was thinking of trying to find a Dura Lite brand as it offers a 7 Year warranty..

Should i replace this CAC or just let it be as its a small leak? Also i sprayed it with Soapy water and its leaking towards the top on both sides pretty much across from each other

[tree98]

Absolutely do not buy an aftermarket cac. They don't have as good of flow internally and will cost you a lot in fuel mileage.

[Rawze]

Stop getting duped by aftermarket S#it products.!!! What good is that Duraf#$uck P.O.S. lasting all those years if it is goign to cost you $8,000 / year in fuel maileage and other losses. -- STICK TO OEM!!! when it comes to CAC unit.

Here is a thread on them worth reading through...
http://rawze.com/forums/showthread.php?t...94#pid2794

I have seen a lot of people with them and they do cause a lot of grief due to their very restrictive flow. Count the number of air passages across the CAC unit, then go look at the duras#iet and count them up. (or most other aftermarket units).. and you will quickly find out they are problematic.

Detroit Rad is not much better. Here is one i inspected for someone a while back...
http://rawze.com/forums/showthread.php?t...5#pid15105


And don't even get me started on the destroyed engine's that I have seen when people use aftermarket EGR coolers...
http://rawze.com/forums/showthread.php?t...02#pid2802


That out of the way, any leak measurable = fuel mileage losses ... but the general rule of thumb is more than 10 PSI loss on a leak test in one minute. - You should not just test the CAC though,.. you should test the entire engine. Block plate of some sort at the intake of the turbo, and at the turbo exhaust outlet.. pressurize whole engine to 30+ psi. looks for leaks in entire engine ... CAC, compressor, EGR circuits, exhaust manifold, ... anywhere.

[Pete1990]

(05-16-2020 )Rawze Wrote:  Stop getting duped by aftermarket S#it products.!!! ...

I Was reading that and couple others and decided to go with a OEM one. At 30 PSI its leaking 5 PSI every 1 and half mins. Trying to decide if its even worth throwing a new one on. Truck has 680k.

[Rawze]

(05-16-2020 )Pete1990 Wrote:  

(05-16-2020 )Rawze Wrote:  Stop getting duped by aftermarket S#it products.!!! ...

I Was reading that and couple others and decided to go with a OEM one. At 30 PSI its leaking 5 PSI every 1 and half mins. Trying to decide if its even worth throwing a new one on. Truck has 680k.

Your not likely to see any fuel mileage gains enough to compensate replacing it based on that leak rate alone. Just be sure to fix any other leaks in the engine while your testing things so they are not compounded. had a guy here one time who had horrible fuel mileage ... we pressurized whole engine up and his air compressor head was blasting boost air from the turbo into his crank case. Sometimes you find the problems in the strangest of places.

[Pete1990]

(05-16-2020 )Rawze Wrote:  

(05-16-2020 )Pete1990 Wrote:  

(05-16-2020 )Rawze Wrote:  Stop getting duped by aftermarket S#it products.!!! ...

I Was reading that and couple others and decided to go with a OEM one. At 30 PSI its leaking 5 PSI every 1 and half mins. Trying to decide if its even worth throwing a new one on. Truck has 680k.

Your not likely to see any fuel mileage gains enough to compensate replacing it based on that leak rate alone. Just be sure to fix any other leaks in the engine while your testing things so they are not compounded. had a guy here one time who had horrible fuel mileage ... we pressurized whole engine up and his air compressor head was blasting boost air from the turbo into his crank case. Sometimes you find the problems in the strangest of places.

Thanks i use a Smoke machine and put a trashbag behind the air filter and pressure the system normally. But i kinda had a feeling my CAC was leaking as i hear it when i left off the boost right now. Think ill just grab an OEM CAC and put it on. I tested the boots one by one and 1 was leaking and didn't find any leaks about 3 months ago on the intake system. I Did buy all new boots anyway and clamps. Fleetpride gave a decent deal on them so i said sure why not lol $70 for all the hoses and clamps

[Waterloo]

If you have not replaced your crankshaft damper it is time... 500,000 mile lifespan, then they start to dry out and can even grenade on you. There is no way to visually inspect either. Use an OEM Cummins unit, take it home with you and paint the heck out of it and mark your timing letters so that they are easy to find/read. Clearcoat with some automotive paint if you have the time. No paint, no warranty. The dealers/shops will not paint in most cases if you have them install.

I would also install new crankshaft and camshaft timing sensors, they are both the same part numbers.

[Pete1990]

(05-17-2020 )Waterloo Wrote:  If you have not replaced your crankshaft damper it is time... 500,000 mile lifespan, then they start to dry out and can even grenade on you. There is no way to visually inspect either. Use an OEM Cummins unit, take it home with you and paint the heck out of it and mark your timing letters so that they are easy to find/read. Clearcoat with some automotive paint if you have the time. No paint, no warranty. The dealers/shops will not paint in most cases if you have them install.

I would also install new crankshaft and camshaft timing sensors, they are both the same part numbers.

Mine is already replaced just had a rebuild last year. I'm not sure if the crankshaft timing sensor was replaced or not but i know the crankshaft was.

[Waterloo]

They never replace the sensors, trust me on that. I would replace, as they do wear out, mainly heat. I think I paid around $30 ea for the two, cam and crank, in my CM-871.