Some advice needed on de-carb service
05-26-2011, 08:58 AM
#1
Some advice needed on de-carb service
My '05 8 has about 54k miles on it and I've always stayed current on my maintenance and never had any major issues. I was considering doing a de-carbon through the dealer and they quoted me about $160 and recommended I change the spark plugs during the service. I told him I had recently replaced the spark plugs but asked if I should I wait until my next oil change or replace anything else in conjunction of the de-carb, and the dealer responded, "I talked to our Master Tech, and he is actually hesitant about decarbing it with it having 54k miles on it and it possibly never having been done before. He has seen cases where decarbing that high mileage of an RX-8 engine actually reduced compression"
any thoughts guys? is that a possible risk? I was assuming this service would improve engine function slightly and something that really should be done.
any thoughts guys? is that a possible risk? I was assuming this service would improve engine function slightly and something that really should be done.
05-26-2011, 10:03 AM
#2
about "reverse-compression"...
There is a chance that it could cause a loss of compression, as the seals of your engine have formed with the internals.
By removing the carbon deposits in your engine, you are creating less surface area, thus decreasing compression...
HOWEVER, that's not necessarily going to happen. The carbon build-up in our engine is MOSTLY in the exhaust port, meaning that your rotors/ housings/apex seals won't be affected. The sea-foam/zoom zoom process will get rid of the carbon in your exhaust port, thus allowing your engine to breath better.
I have heard of people loosing compression after the service, but I hear more success than failure...
Were I you, I'd decarbon the engine.
There is a chance that it could cause a loss of compression, as the seals of your engine have formed with the internals.
By removing the carbon deposits in your engine, you are creating less surface area, thus decreasing compression...
HOWEVER, that's not necessarily going to happen. The carbon build-up in our engine is MOSTLY in the exhaust port, meaning that your rotors/ housings/apex seals won't be affected. The sea-foam/zoom zoom process will get rid of the carbon in your exhaust port, thus allowing your engine to breath better.
I have heard of people loosing compression after the service, but I hear more success than failure...
Were I you, I'd decarbon the engine.
05-27-2011, 01:33 AM
#8
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I have an '04 w/ 52k, and my warranty is up in a couple of weeks. I had read here before that people said Mazda reimbursed their compression check costs if the engine failed. I'm bringing mine in for the decarb and compression check before the warranty is up, so I asked the local dealership's service manager about this. He said that Mazda will only reimburse the diagnosis fee if the car is under the base or powertrain warranty.
05-27-2011, 08:03 AM
#9
I have an '04 w/ 52k, and my warranty is up in a couple of weeks. I had read here before that people said Mazda reimbursed their compression check costs if the engine failed. I'm bringing mine in for the decarb and compression check before the warranty is up, so I asked the local dealership's service manager about this. He said that Mazda will only reimburse the diagnosis fee if the car is under the base or powertrain warranty.
If not, let the manager know that the decarb is covered under the 100k/8year engine core warranty, then ask him if he'd like to leave his job and you can do the rest of the homework for him...
05-27-2011, 01:58 PM
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RX8Soldier, are you sure that it's always covered by Mazda under the 8yr/100k warranty? I specifically mentioned that I had read that Mazda will reimburse for the compression check if an engine fails under warranty, and that was the response I got. It's from the service department that most RX8club members hold in very high regard here in the Greater Phoenix area.
05-27-2011, 07:05 PM
#12
A lot of reduced compression comes from stuck side seals. If you decarb, it should loosen up the gunk in the side seal groove, which will allow the side seal to move much more freely, and increase compression. A seal stuck up (or even worse, down) will allow combustion gasses to go all over the place.
05-27-2011, 11:08 PM
#13
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RX8Soldier, are you sure that it's always covered by Mazda under the 8yr/100k warranty? I specifically mentioned that I had read that Mazda will reimburse for the compression check if an engine fails under warranty, and that was the response I got. It's from the service department that most RX8club members hold in very high regard here in the Greater Phoenix area.
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