CAT C7 questions

mmills023

mmills023

Member
Mar 6, 2018
107
Chicago, IL
Boat Info
2002 Sea Ray 400 Sedan Bridge
Engines
Cat C7's
Question for the folks a lot smarter than I am! I am looking at a boat that has CAT C7 engines in it (2002 searay 400 Sedan bridge) I called ring power (cat dealer) and they sent me the service information and also a service schedule. It says that the aftercooler core should be replaced every 6 years. I have looked around and can’t find any detail on what is involved in doing this or relative costs.

Does anyone have any experience with this or thoughts on the necessity of performing this?

I should say the engines have 780 hours on them, have had the 250 hour service performed and oil and filters every year.

Any help would be appreciated. Thank you!
 
I can't imagine why they would need to be replaced, but I would at least remove them and take them to a radiator shop for cleaning and pressure testing. The results of that may be enough if they test out ok. I would bet that you are looking at $1200-1500 per side to replace (guessing), versus $150-200 for cleaning and testing. I did my aftercoolers myself this past summer, removed them myself, took them to a shop for cleaning/testing, and then reinstalled myself. It was not a bad job. I have 3116s though, not sure if there's something wildly different about C7s. Frank should be along shortly to chime in I'm sure.

Kevin
 
All Caterpillar maintenance recommendations carry that feature, i.e. replace the after coolers. It is at varying intervals depending upon what engine you have. The reason is that most after coolers for about 350hp engines are seawater cooled meaning seawater passes thru the core to cool in intake air. If you get a leak in the core and your engine ingests seawater, there is almost no chance the engine will survive if you are producing power and the engine is under load. You could periodically remove, inspect and clean the aftercooler and you will very likely be replacing it before 6000 hours anyway.

This is not a job to "cheap out" on for several reasons. From a work complexity standpoint it is just taking stuff off and putting it back on, but these guys are heavy and difficult to handle because they are the length of the engine. There are a lot of hoses for air and water involved that should be replaced when the after cooler is removed. I want someone who has done this job before to see after cooler and deal with those hoses because crimping one or getting a bad seal can easily mean removing the aftercooler again to fix the problem. It is about 8 hours work on the boat and another 4-5 in the shop cleaning the core….figure $2500.

If the after cooler needs to be replaced, on a 3126, the cost is about $3200 each; I suspect, but don't know for sure, that the C-7 is comparable.


For you 3116 owners:

The 3116 is a different breed of Cat (that was an accident; no pun was intended!) because the aftercoolers are jacket cooled meaning that engine coolant is the cooling means, not seawater.
the coolers are lighter and there are no lime deposits in the cooling side as long as you are running Cat ELC for coolant. The work, however is the same except the cleaning labor is less because the antifreeze side should be clear if you have kept up with the recommended replacement schedule for the coolant and you use ELC. I just finished this on my boat (1996 with 1500 hours)and was a bit surprised at the condition of the hoses and hose clamps. I had already decided to change all of them anyway and it was a good thing because they were in poor condition. All the gaskets, all new hoses, hose clamps (Cat has upgraded the hoses to formed silicone rubber and Cat hose clamps are superior to aftermarket) and new ELC, plus since we were draining all the coolant, I changed the thermostats and the expansion tank radiator caps at the same time so the parts total was about $525. My aftercoolers were in excellent condition but did need to have the inlet side cleaned. The labor done by a Cat mechanic was about $2500.
 
fwebster said:
All Caterpillar maintenance recommendations carry that feature, i.e. replace the after coolers. It is at varying intervals depending upon what engine you have. The reason is that most after coolers for about 350hp engines are seawater cooled meaning seawater passes thru the core to cool in intake air. If you get a leak in the core and your engine ingests seawater, there is almost no chance the engine will survive if you are producing power and the engine is under load. You could periodically remove, inspect and clean the aftercooler and you will very likely be replacing it before 6000 hours anyway.

This is not a job to "cheap out" on for several reasons. From a work complexity standpoint it is just taking stuff off and putting it back on, but these guys are heavy and difficult to handle because they are the length of the engine. There are a lot of hoses for air and water involved that should be replaced when the after cooler is removed. I want someone who has done this job before to see after cooler and deal with those hoses because crimping one or getting a bad seal can easily mean removing the aftercooler again to fix the problem. It is about 8 hours work on the boat and another 4-5 in the shop cleaning the core….figure $2500.

If the after cooler needs to be replaced, on a 3126, the cost is about $3200 each; I suspect, but don't know for sure, that the C-7 is comparable.


For you 3116 owners:

The 3116 is a different breed of Cat (that was an accident; no pun was intended!) because the aftercoolers are jacket cooled meaning that engine coolant is the cooling means, not seawater.
the coolers are lighter and there are no lime deposits in the cooling side as long as you are running Cat ELC for coolant. The work, however is the same except the cleaning labor is less because the antifreeze side should be clear if you have kept up with the recommended replacement schedule for the coolant and you use ELC. I just finished this on my boat (1996 with 1500 hours)and was a bit surprised at the condition of the hoses and hose clamps. I had already decided to change all of them anyway and it was a good thing because they were in poor condition. All the gaskets, all new hoses, hose clamps (Cat has upgraded the hoses to formed silicone rubber and Cat hose clamps are superior to aftermarket) and new ELC, plus since we were draining all the coolant, I changed the thermostats and the expansion tank radiator caps at the same time so the parts total was about $525. My aftercoolers were in excellent condition but did need to have the inlet side cleaned. The labor done by a Cat mechanic was about $2500.
Click to expand...


Frank - super helpful for sure! - curious, your comment about the 2500.00 (i know aprox.) is that a "per engine" cost, or to do both? I am trying to understand what i could have to pay out. The boat runs great, but they have never been inspected so before I buy I have a chance to negotiate based on possible costs. I want to be fair, but protected.

Thank you again for the help!

Mike
 
No, that is both engines

If I can offer a suggestion………..if you aren't interested, just ignore it. But, you are micro managing this purchase. This is a highly desirable boat, i.e. high demand plus significantly upgraded engines. It won't be on the market long. The way the buying process works is that the boat is for sale to the first buyer who make an acceptable offer. So if you are really interested, you need to get the boat off the market by making an offer, getting it accepted by the seller, making a deposit and get a signed contract, contingent upon your surveys. Then have the boat surveyed and the engines evaluated. If you spend the time and money on a mechanic now, you may just find the boat is sold out from under you. Key items to note….a offer, the offer acceptance, a deposit and the agreement in writing.

Last, what your future maintenance costs are or may be at a point down the road mean nothing in this deal. No seller is going to reduce a price for something like after coolers that may need replacement 5000 hours down the road. In typical recreational use, this is close to 30 years away and not a concern to over analyze at this point. Deferred maintenance is another issue…….for example if the 250 hour valve adjustment had not been done and the boat is at 900 hours, then it is a legitimate ask to make the deal include catching up that service. The time to make a request like that is after you have done your surveys and it is time to accept or reject the boat……not now.
 
Are you sure they are C7 engines and not 3126B’s, From what I know, might be wrong, but C-7 engines didn't appear until 2003
 
Frank, I plan on doing the same thing to my 3116s this year, 950 hrs, and ai think they are original hoses. Would share the parts list of the hoses and things you replaced?

Thanks, Randy
 
Frank, do you happen to know the recommended hours that they should be removed on the 3126’s?
 
I can’t. I’m on the boat in Florida and my receipts are in Tennessee since I buy my Cat parts off the water from a construction equipment dealer in Nashville to save $$.

It is a long list of mostly smaller parts. Since you are going to have to go to a Cat dealer anyway, take your serial no’s abs AR # to the parts desk and tell them you are going to clean your aftercoolers and you want to replace every hose and hose clamp involved plus the sftercooler gaskets.

You are going to have to drain all the coolant so you may want to get thermostats, gaskets and expansion tank hoses and clamps as well as 20 gal of Cat ELC coolant.

If you want copies of my receipts I can send them after we return to Tennessee.
 
That would be Great, Don't plan on doing them till later on in the year. I want to replace everything while I'm into it, No use cutting corners. Thanks for your help. 450 DA, 3116 Cats, Great boat !!
 
fwebster said:
No, that is both engines

If I can offer a suggestion………..if you aren't interested, just ignore it. But, you are micro managing this purchase. This is a highly desirable boat, i.e. high demand plus significantly upgraded engines. It won't be on the market long. The way the buying process works is that the boat is for sale to the first buyer who make an acceptable offer. So if you are really interested, you need to get the boat off the market by making an offer, getting it accepted by the seller, making a deposit and get a signed contract, contingent upon your surveys. Then have the boat surveyed and the engines evaluated. If you spend the time and money on a mechanic now, you may just find the boat is sold out from under you. Key items to note….a offer, the offer acceptance, a deposit and the agreement in writing.

Last, what your future maintenance costs are or may be at a point down the road mean nothing in this deal. No seller is going to reduce a price for something like after coolers that may need replacement 5000 hours down the road. In typical recreational use, this is close to 30 years away and not a concern to over analyze at this point. Deferred maintenance is another issue…….for example if the 250 hour valve adjustment had not been done and the boat is at 900 hours, then it is a legitimate ask to make the deal include catching up that service. The time to make a request like that is after you have done your surveys and it is time to accept or reject the boat……not now.
Click to expand...

Thanks Frank - I should have been more clear. I have made an offer, it has been accepted and I am doing the surveys. This was something uncovered as part of the survey, and I was looking for some "real world" thoughts. Your information has been really helpful. Thank you again!
 
doozie said:
Are you sure they are C7 engines and not 3126B’s, From what I know, might be wrong, but C-7 engines didn't appear until 2003
Click to expand...

I'm with Doozle. The first 3126's were "MUI" - Mechanical Unit Injectors. Then came the 3126Bs with "HEUI" - hydraulically activated, electronically controlled, unit injectors. The C-7 took the 3126B (in 2003) and added ACERT NOx reduction technology for lower emissions. My 2003 410 had 3126s (350HP) with serial #'s beginning with 1ZJ. If you have C-7s, your boat has been repowered at some time.

Here's a nice discussion link:

http://capitalremanexchange.com/cat-c7-specs-and-engine-history/
 
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If you read his earlier post, he has already verified the engine change to C-7's with Ring Power who is the Cat dealer in Florida Sea Ray works thru and who provided the C-7's.

Also, I think you are missing one 3126 version…….The 3126B (and the 3116 as well) was replaced in about 2002 by the 3126E which had electronic injectors. The HP rating on the 3126E was 350hp. Carter, if you recall, the previous owner of your 410 had the pump "turned up" to what he guessed was 385 hp……for no reason other than he could…... but there were no 385 hp specs on the "E" engine so the final output was a guess.
 
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