So, I purchased my 03 CLS 6MT about 3 years ago with this rough idle and low power. I figured one of the coils were bad because they car only had 94k miles on it and the seller stated it needed a tune up, dummy me. So, I replaced all the coils, timing belt and water pump job, spark plugs and all. seemed like the car was running better but the rough idle and lack of power was still there. I didn't really care much over time because I used the CL as a commuter car 3-4 times a week. I've put about 30k miles on it over the 3 year time frame and I really wanted to know what the issue was. After reading some other posts and given my car is a 6MT I assumed that maybe someone mis-shifted and bent valves so I did a compression test with the results posted below. Now that I have this issue with two of the cylinders generating low PSI I need some advice on what to do. Should I just replace the motor? Keep driving it like it is until something happens? Take the heads off and have them redone? What do you guys think? Or can adjusting the valves resolve the issue?

Cylinder 1= 90psi
Cylinder 2=210psi
Cylinder 3=175psi
Cylinder 4=175psi
Cylinder 5=175psi
Cylinder 6=110psi

 

If you can find a J35A3 '00-02 MDX you can swap that in with a few modifications. Check out the thread below for all the details:

https://acurazine.com/forums/second-...s-cls6-915106/

 

do a leak down test to show if the heads are really fucked. if heads are really fucked, you can either buy used set of heads or send out heads to be machined

 

I'm thinking a valve adjustment may have been beneficial at some time in the past; that said, if a valve adjustment was the cause, after 30,000 miles and three years, the valves are most likely beyond the point where said adjustment will have helped.

Long story short, I'm inclined o agree with Justin's assessment.

 

i agree, so i priced heads for the cl and they are averaging about 300-500 bucks just for the heads. considering the heads with the cost of head gasket kit costs just as much as a replacement motor. ill continue to find heads to see how much that will cost.

I'm going to stay away from the mdx swap, looks weird. lol

 

are the manual heads different from the automatic ones?

 

Your other option is to have your current heads reconditioned; I have no idea what it costs to recondition a J-Series head, but I'm pretty sure you can have quality work done for the price quoted above, or less, possibly substantially less.

 

I'm 99.5% sure they are identical.

One other comment, Justin recommended a cylinder leak down test in a post above, did you have such a test performed?

 

no i haven't had a leak down test performed. i need to take it somewhere to have it done i don't have that ability. any suggestions on where?

reconditioning the head i would assume be the purchase of new valves and seals? just assuming?

 

How so?

 

KingBattle, these are the options you have; Oh, and BTW, the J32A2 heads from an automatic transmission '02-03 TL-S and CL-S ARE different from your '03 6-speed heads. With that said you could potentially consider the following:

Redo your original head(s). Call around to local cylinder head shops/machine shops explain what you have and what needs to be done, acquire quotes, weigh the costs and go from there.

You can 'roll the dice' and TRY to find a low mileage/low cost 6-speed CL-S J32A2 that runs properly. Good Luck with that. Search car-part.com for your vicinity, there could be one down the street. Then you have a 'plug & play' engine that can be installed directly into the car with no modifications.

Or, you can TRY and find a low mileage/low cost J32A2 from an automatic '02-03 TL-S/CL-S that runs properly. The odds of finding one are higher than the 6-speed CL because you have two models to choose from, where they (Acura) made more; thus, increasing your odds.

The downside of the automatic is that you or your installer will have to swap over the 6-speed J32 timing gear, pulley side crank sensor & bracket, front cam gear, backing plate & sensors/harness from your old engine. This will make your sourced automatic J32A2 compatible to the rest of your 6-speed car.

The above swapping of '6-speed gear' is exactly what you would have to do if you opted to upgrade to a J35A3 '00-02 MDX engine.

 

I was in this scenario awhile back and opted to go with the mdx swap... wasnt any more technical than swapping a automatic j32a2... found one for 500 bucks out of a totaled mdx with 70ish k... went ahead and did a timing belt/water pump and all the correlating parts out of my old and tired stock motor and swapped them onto the the j35...

best move I could have done the extra tq down low makes for much easier city driving.. that extra tq is just compounded by the mods I had with the original motor..

the mdx swap is the mvp choice here..

 

I also did an MDX head swap into my 3G TL six speed

 

Did you have to swap over any kind of 'stuff' from your six speed heads to the MDX heads, just curiuos?

 

swapped 3.5l type-s cams into 3.7l MDX heads.
but other than that, straight swap.


I did "feel my buttdyno" improve mid-range...but wasnt tuned and i like top end better.
OCD kicked in and i tore the engine down again, but forgot to install something...and fucked the bottom end...

ended up replacing the whole engine with junk yard motor J32a3...stock 2005 TL motor
if i had to do it again, I'd get tuned first.

 

It will be interesting to see what option the OP elects, should he come back with an update. He's probably feeling a little 'overwhelmed' at this point.

 

I'm still trying to figure out what "looks weird" about an MDX head swap

 

I was super overwhelemed at the options I had. and it was my first time EVER doing a head swap. needless to say, I learned a lot and why I fucked the bottom end.. I forgot to install the little pin that goes into the crank pulley. which rotated the crank assembly when i tried to start her up. after a few starts, the engine binded. (bound?) lol the engine locked up

 

Just a guess; however, If I had to speculate, it's because of whats involved with swapping the '6-speed head items' over to the MDX heads to make the J35A3 compatible. Let's face it, there is a higher level of 'critical thinking', mechanical DIY skillsets and the availability of proper tools needed to plan it ALL out and then execute the WHOLE swap, IMHO.

 

I think it's "weird" since the intake manifold is propped higher with the IM spacer, except for that I got nothing..

As for whether you should go with the J35A3.. it's quite amusing shredding tire in 3rd gear, ask me how I know..

 

Thanks for all your posts they were very helpful. ALL OF THEM.. I'm weighing all of the options and I'm leaning towards getting the heads rebuilt unless I can find a manual six speed motor which seems very hard.

The MDX swap looks weird only because of the high intake manifold and I was trying to find the benefits for doing the swap outside of more torque. Not that more torque is a bad thing but I'd like to keep the car as original as i can since they are becoming rarer. For example I've been trying to find an all original Acura GSR or type r, if they are modified the value is in the crapper.

I have this really good machine shop not to far from my house called c&c they've done a ton of work for me on my Chevelle and old turbo Integra. I've been trying to get them on the phone the last two days, I may drive over if I can get them by lunch time to get a price quote.

does anyone know about the leak-down test? who will be able to do that??

 

I was able to rent a leakdown tester at napa and oreilly in the past... you can do it yourself if you are handy... take a spark plug out and insert a pressure gauge.. there are a ton of videos online for a tutorial...

 

... There's no way. Maybe if you just dump the clutch from a high rev or something, but you can't get more than a chirp from 2nd->3rd.

My first gear is useless for traction, but I can't spin 3rd gear and I only have 215 tires.

 

Don't know what to tell you, did it almost daily. I'd post a video but she's gone to greater pastures..

 

mdx swap here with blower lol. good choice. mine is currently doing the same thing, pretty sure its valves, have a nice set of j32a2 heads ready to go on.