1990 Maxima coolant leak between engine and trans

Post by **PapaTom** » Wed Apr 22, 2009 7:08 pm

Is there a freeze plug between the engine and transmission? It's an automatic. Could there be a freeze plug behind the flexplate? Coolant all of a sudden started pouring out from under just behind the oil pan where it meets the transmission

I'm gonna start pulling out the transmission tomorrow morning. I'll try to post up pics for future needs
Modified by PapaTom at 11:14 PM 4/22/2009

Post by **PapaTom** » Thu Apr 23, 2009 7:53 pm

Well, after 5 hours of labor I got the Transmission and engine out of the car. I discovered I also need the drivers side axle shaft.

I found that out of 3 freeze plugs behind the flexplate, one is severely corroded. I'm replacing ALL of them.

Since the engine is out and so many components are off, I'm also replacing the timing belt, all acessory belts, valve cover gaskets, front motor mount, oil pan gasket, rear main seal even though its not leaking (yet)...may as well since it's right there. Also both front struts and all spark plugs. Oh yeah, fresh fuilds and filters on engine and transmission.

This car is gonna ride even smoother than before! It ran great except for the one faulty freeze plug. Must have finally given out during a heat wave we had when temps went into the high 90's. It just couldn't handle the heat/pressure.

Will be done by tomorrow night, except for the alignment on Saturday

Post by **MinisterofDOOM** » Thu Apr 23, 2009 8:07 pm

Glad to hear another 3rd gen owner's giving his car the attention it deserves.

Post by **PapaTom** » Fri Apr 24, 2009 9:19 pm

Well I'm done with everything except front struts. I ended up replacing all the freeze plugs. Firewall side had another bad one I didn't even know about. It was covered in oil dripping from the valve cover gasket.

I had an interesting time removing the upper intake AND distributor just to remove the radiator side valve cover!

Since I removed the intake, I replaced all dry vacuum lines. it's definitely worth it. It ran fine before, now breathing and sparking better......well, I'm excited to see the difference.

Here are a few pics:

plug under firewall side engine mount:

3 plugs behind flexplate

Post by **MinisterofDOOM** » Fri Apr 24, 2009 9:45 pm

Yeah, I did most of my vacuum lines a couple summers ago and it made a big difference. Definitely worth doing. Most of them were rock hard and just waiting for a harsh jarring to shatter them.

Post by **PapaTom** » Tue Apr 28, 2009 9:45 am

Well, everything is in the car and entire engine bay and undercarriage was steam cleaned. It starts but runs kinda sluggish and idles rough. I'm not sure where to set the timing. The Chiltons book say 20 degrees BDC, but indicates the notches on the lower dampener are 0, 10, 20, 30 and 40. When I had set it to TDC when changing the timing belt, the camshaft sprockets, crankshaft sprockets and rotor were pointing to TDC when the timing indicator was at the 40 degree mark. When I installed the new timing belt nothing moved and everything was assembled in reverse order to ensure nothing was out of place.

Now I'm stumped. It starts, idles, accelerates slow and sluggish no matter where I set the timing mark. I'm going to check the vacuum lines again. I may have missed something.

Post by **GRNMAXDMON** » Thu Apr 30, 2009 9:06 am

glad to see you fixed the main problem but a new arose. these are strong cars and its good to see that you did this while the engine was out. the idling issue has me stumped as well. not even i know what can/is causing but most likely it might be the timing. try going to maxima.org and ask there.

Post by **lightsout** » Thu Apr 30, 2009 4:11 pm

u must have missed a vacuum line...thats gotta be it man. find that vacuum leak and kick it like a

Post by **PapaTom** » Fri May 01, 2009 7:17 am

Well, I left it at my friends local shop. It had a previous check engine light on and is still on. In the process of re-checking all the lines, I noticed I missed a hose leading from the intake to a device on the firewall. The lead comes out just above spark plug #1, pointing towards firewall. It runs a small hose to a device right in the middle of the fire wall below the rubber weather seal.

Does anyone know what that device is? Someone suggested MAP sensor

Post by **PapaTom** » Fri May 01, 2009 7:20 am

By the way, once everything was in the car and running, I removed the front timing cover to re-check my timing belt installation. It looks fine and good tennsion is there. All the alignment marks line up well so I have to hope it's just a vacuum leak or sensor issue.

I'll fin out soon. It's being diagnosed right now

Post by **ABNRML4U** » Fri May 01, 2009 1:21 pm

So, did you fix it How is the Max running?

Post by **PapaTom** » Sat May 02, 2009 11:28 am

Still in the shop. Turns out it needs a MAF sensor and knock sensor. Where is the knock sensor located? If it's easy I'll just have him skip it and I'll do both sensors.

There's also back pressure in the exhaust. Possible timing issue or catalytic convertor clogged up

Post by **GRNMAXDMON** » Sun May 03, 2009 5:30 pm

PapaTom wrote:Still in the shop. Turns out it needs a MAF sensor and knock sensor. Where is the knock sensor located? If it's easy I'll just have him skip it and I'll do both sensors.

There's also back pressure in the exhaust. Possible timing issue or catalytic convertor clogged up

if i recall, the knock sensor is right under the lower intake plenum between the cylinder heads. you would have to remove the upper and lower intake plenum or try and get someone with small enough hands to squeeze in between all that and you might be able to get to it and install the new one.

Post by **PapaTom** » Fri May 08, 2009 5:51 pm

turns out that the timing belt was done perfectly. the problem was the wiring harness for rear cylinder bank. still have a minor vacuum leak, but car runs soooooo much better than before

1990 Maxima coolant leak between engine and trans

1990 Maxima coolant leak between engine and trans

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