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Hey all- just wanted to introduce myself and share my experience with recently doing an engine/tranny transplant on a relative’s 04 EX sedan auto. I lurked for a bit and used quite a few articles and threads. This was a straight stock for stock- as this person cares zero about performance, but instead reliability and is a secondary/commuter car. First time doing major work to a Honda and this car was really easy to do the transplant.
Long version:
Some background about myself- I love working on cars though my projects recently involve later 90s Chevy, earlier a Nissan and a Toyota, so this was the first major Honda project though I do have a Honda CBR bike. The Chevy is still in the garage so I had to work outside.
Anyway long story short- with 210k miles overheated in August when it was hot. I finally traced it down to a dead radiator fan, in combination with a really hot day and my relative still driving the car. It might have also been head gasket but I'm not sure which came first- water under the bridge at this point. It got so hot it melted the plastic timing cover and other parts. Had to be towed. As many of you know, for this gen car, most boneyard engines are 100K+ miles, but I got lucky and found a good deal on a 02 junkyard motor with only 32k from one that was hit on the passenger doors- so it was in pristine shape, decided to get the transmission too. Was about 150 miles away but a fun little road trip. Did some work on the replacement engine while it was out of the car, including changing the timing belt and rear main seal.
Compared to other cars I’ve worked on- this was a breeze to do the transplant. Everything came out and went back in fairly smooth- didn’t have to undo the A/C or power steering lines and the hood didn’t even have to come off. I also like how the wiring harness just unplugs from the ECU and comes out as one. It took me about 2 months to do, really taking my time - as I’ve been out of town or busy with other stuff but got it done before cold weather here in the mid-Atlantic.
So far I’ve put about 200 miles on the “new” motor and trans and it’s working great! No funny noises and no check engine light. I definitely relied on some of the articles and threads here. I realize dollar for dollar it probably wasn’t “worth” it, but having an extra car running again and the satisfaction of doing myself is hard to beat.
Major lessons
Put the driver’s side radiator fan in before putting the engine back in- you can still put it in by removing the radiator but I made that mistake and had to drain, remove then reburp the radiator
When changing engines between years- swap the wiring harness or make damn sure the wires are the same. My junkyard motor had the complete harness and I thought I could get away with not switching the harness and it came back to bite me. Newer models have more wires to the O2 sensor, even though everything clipped in but it instantly threw a check engine light
Check the rear main seal - the older models had a TSB and I found this one to be slightly leaking
Related - on a D17A2 You must drop the oil pan in order to replace the rear main seal
Buy the aftermarket plastic push pins for the splash guards since ½ of mine came out broken lol
Some pictures below.
Old engine coming out
Donor car
At the bone yard collecting the loot
Got her home...
Prepping "new" engine- dropped oil pan to change rear main seal
Engine and trans about ready to go in
Putting in the new engine
Complete!
Last edited by cbrc5eric; Nov 10, 2017 at 09:30 AM.
Did you put a new head gasket on the replacement while it was out?
I did not- I actually debated this one back and forth as I was half way there- primarily it was out of a running car, compression/leak down checked out and the junkyard gave a 90 day warranty. They said it's void if the engine was disassembled by taking the head off. I know they put heat tabs on it and not sure if they'd be able to tell but didn't want to run the risk of voiding the warranty. Also, these projects have a tendency to "while I'm in there.. might as well" snowball effect, which happened to the Chevy (now off the road for 2 years lol). For the Civic, the plan is- I'll likely do the head gasket and valve job when it's timing belt change time again- by then the engine will have 90-100k miles and the body 300k lol.
Originally Posted by sdaidoji
great job!
moved to engine swap section as success story :P
Introduction and 04 EX Transplant success! 
