Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Link between engine replacement and clutch?

2007 Nissan Sentra (6 speed manual). 80+K miles. Engine was replaced (I’ll spare the details). Less than 3 months later, the clutch goes. What’s the chance that these are related? Clutch was never replaced and was deemed fine when the engine transplant was done. Also, what would be an average price to have the clutch assembly replaced?

“the clutch goes”

Spare the details on the engine if you wish, but its impossible to comment if you spare the details on the clutch. “The” clutch is actually a whole system of things. You need to get very specific about what failed and how.

Any difference in how the clutch acted after the swap? And now you know, any time the engine or tranny is out, a new clutch goes in.

From the info provided there should not be a “link”. If the clutch operated smoothly after the installed motor then everything would seemingly be aligned properly. It could be the flywheel on the new motor was damaged in the removal and shipping process. Does the OP know if his original flywheel was installed or did they use the flywheel that came on the replacement motor?

It might be best to replace a clutch in a motor switch to start off with smooth surfaces that then wear in together. The gouges in the flywheel and gouges and marks in the clutch disk and pressure plate are misaligned by nature and the wear in process could accelerate the loss of material from the clutch disk. Same idea as changing brake pads without resurfacing or replacing the rotors. The new pads can wear quickly as they mate up to the old rotors.

the engine was replaced because of several missed oil changes leading to no oil in the engine and the engine ran terrible afterwards. nursed it along for several months but then it wouldn’t run

the clutch did not seem to act differently after the swap. I did hear some high pitch noise at high RPM when the oil was changed soon after the swap.

while driving down I-65 outside of Indianapolis, power to the engine stopped. the engine was running but i was coasting. after that, i could not get it into gear.

I have had a few different opinions. One mechanic (Nissan dealer) stated that the swap and the clutch are unrelated because you wouldn’t have to do anything to the clutch for the swap. Another said that it’s not possible to tell until the real cause is found. The mechanic who did the swap said that they are unrelated (without looking for the true cause yet) because if they did something wrong it would have happened right away. For what it’s worth, at the time of the swap, they said they checked the clutch and it was fine.

thanks for the feedback.

Clarify: When you say you could not get it into gear, do you mean that you physically could not push the shifter into gear, or that once you put the shifter into gear and tried to drive, the car didn’t move?

We also need to know what it means to say that power to the engine stopped but that the engine was still running.

I am thinking that something happened to the hydraulics in the clutch (my guess is a leak, probably caused by the motor swap… I don’t know if you have a hydraulic throw out or a leaver on this car, but I bet that’s your issue. If you pop the hood you should see a little fluid reservoir next to the master cyl, does it still have fluid in it??

When I tried to push the shifter to put it into gear, it wouldn’t go into gear. It seemed that that the shifter was in the correct place but it was not in gear.

By no power to the engine, let me see if this helps:
I was traveling on the highway at about 65 mph, there was a strange noise and the rpm’s shot up and then back down. That happened a couple of times and then the rpm’s shot up and stayed up until I eased up on the gas pedal. Basically it came out of gear and would not go back in. I was then just coasting with the engine still running/on. I coasted to the side of the road until I got the tow.

Basically, my dilemma now is whether to trust the original mechanic. When I brought the damaged car in, they immediately said that i needed the clutch replaced and quoted me another 2 grand. I bargained that down, but it still seemed that they would not even entertain the possibility that something happened during the swap.

I can either have them fix it again and hope that they would own up to any mistakes that they find or
I can take it somewhere else where they may or may not find evidence that there was a mistake.

Even if somewhere else finds a mistake, it doesn’t seem that I would have much recourse with the original mechanic.

OK, your clutch itself is probably fine then. It’s not going into gear because it isn’t responding correctly when you press the clutch pedal. This could very well be exactly what gsragtop said - and it’s very likely that your mechanic caused it (the car is too new to have old-age failure of the hydraulics). I’m pretty sure you have a hydraulic clutch on that vehicle, so the mechanic could have bumped a line or failed to hook one up properly, causing a slow leak. Now that the fluid is gone, your clutch no longer disengages so you can put it in gear.

If someone else finds a mistake, and you can get them to declare (in writing) that such a mistake can be caused by an improper engine swap, then it’s possible you can pressure the original shop to cover the repair charge.

If you mean that you can put the shift lever in each gear position but get no reaction the clutch may have come apart or broke. Another possibility is an axle (CV joint) may have come apart. Either one may be a result of leaving something loose when the engine was installed. Has the car been inspected?

With the new description you stated that you were cruising at 65mph, the engine suddenly reved up & down without taking the car with it, and then the engine seemed to disconnect from the car. You were then unable to get it back into gear.

based on that description i’m inclined to not suspect the clutch hydraulics. The hydraulics come into play only to release the clutch when you push the pedal in even if you lost fluid the clutch should not disconnect. UNLESS it was never fully engaged to begin with due to a leaking clutch hydraulic system.

I’m starting to think all of the clutch components weren’t buttoned down completely on the reinstall - loose pressure plate maybe.

wait a second. I misread. I saw “When I tried to push the shifter to put it into gear, it wouldn’t go into gear.” but skipped “It seemed that that the shifter was in the correct place but it was not in gear.”

The others are right. You have a clutch issue.

At 80k They really should have replaced the clutch. They had the engine out. The cost at that point was marginal. Doing a bad job on the replacement costs them double labor or a PO customer. Also possibly they have a bad transmission mount or they messed up the shifter alignment.

I’m going to bet the engine swap was just fine. Probably the only thing that happened is pressure plate failure, which could happen at 250k or 30k. Not to mention when you replace that OEM clutch, you’re gonna put in some POS from the “zone” and that’ll be a real winner. So I guess my question to the OP would have to be “would you have sprung for a couple hundred more dollars for a clutch if your old one looked fine”? I can promise you we give every customer that option when replacing engines in their cars with manual transmissions. I’ll guarantee you at least 90 percent refuse. If it was a botched job, I would have to believe some noise was being made.

thanks for all of the comments. much appreciated.