I have a 2002 Sentra se-r spec v with a vq35de swap out of a 2003 maxima. The other day I was doing the idle relearn and once the car was warm and I completed the relearn I got out and noticed smoke from the rear of the block. Something burning on the y pipe. So I shut the car off and looked above and below, I couldn't find the leak but it was a good amount of coolant. Maybe a quart or so puddling under the car. I'm thinking its the HG because of a previous incident last week.

The previous incident last week, I was driving and the car started bogging like it was in limp mode. So I drove just a little more up the road so I could safely stop and get out. It started to sputter more and the exhaust was more like a subaru at this point... so I got to where i could stop, pop the hood and find a fuel line spraying. Shut the car off, cut the line and reattached so its secure again and the car seemed to be driving fine.

Jump to 5 days later and this leak springs out of nowhere. Now it is coming from basically dead center of the block I believe as it was right over the y pipe. I've done a ton of searching and not really finding anything that I can solidly mark as the problem.

In this picture theres a hole in the block directly below the center exhaust port, where a tube comes off, is this a coolant line or an oil line? I don't have an oil cooler being a sentra and all, so it's just a plugged tube but its got coolant all over it. So either its from that tube or it is from the head gasket above it.


I can't say for sure yet its the HG because the oil isn't milky and I haven't done a compression test. But I'm not sure the compression test would yield any results considering I'm not blowing any smoke from the exhaust or nor is it in the oil. I'm really hoping its not the HG because I don't think I can remove the timing chain cover while the motor is in the car... its a really tight fit.

Any help is greatly appreciated and thank you for your time.

 

That is definitely where a coolant line runs. And you are also spot on that it is from the oil cooler. I understand that it's in a Sentra, but why wouldn't you leave the oil cooler on there? Here's a diagram of how the system should look.

 

So from my understanding of that diagram, those lines are all coolant lines that surround the part where the filter screws on? So part 21302M is a coolant line right? if so then i believe I found my problem.. le sigh. i have to remove my right axle to reach it. lol... it's so tight in there.

To answer your question, I didn't do the swap. I would have left it, however looking underneath my car for the past two days, I'd be willing to bet the line doesn't fit in there. Its an insanely tight squeeze.

Anyways thank you so much for the diagram. I found the very same in quite a few different threads and in the FSM, but I wasn't sure if it was oil or coolant.

 

Nevermind I found my answer. Thanks for the help!!

 

And the answer was...?
Don't leave a thread unfinished.

 

Glad i could help...

 

haha The answer to my question if they are in fact cooling lines. Yeah the issue is when the swap was done, he just plugged all the lines for the oil cooler because they don't fit in the sentra. Well the hose he plugged with on the rear of the block has probably had a slow leak for a while but I had no idea it was there. Then it blew. It's the only thing I can figure looking back there...

So now I'll be taking off my axle to reach it and fix it. I'm just happy its an easier fix.

 

No problem. And yes, they are all coolant lines. Glad it's an easy fix for you. Those are the best kind. Not sure why they wouldn't fit in the Sentra. All of those lines hug the contour of the engine block.

 

I believe because of how close the axle is. While I'm fixing it if I can run the lines I will. Maybe reroute with longer hosing or something.