RE: 2005 Nissan Sentra 1.8l Head gasket replacement questio

[eric zabin]

Hello All,

I have to replace a head gasket on my Nissan Sentra 2005 1.8L engine. Can anyone inform me as to whether the timing chain needs to be removed prior to removing the head? The Hayes manual is not clear on this issue. Thanks in advance.

Thanks,

EZabin

[Razi]

Here's the Factory Service Manual for your car.
http://www.nicoclub.com/FSM/Sentra/2005_Sentra/
I recommend you save all the files onto a folder on your computer since it is very handy.

Your timing chain might not need to be completely removed, just unhooked from the cam gears.
Make sure the chain doesn't fall down or skip a tooth on the crankshaft gear though.

[eric zabin]

Hi Razi,

Thanks for your quick reply. And the link with the information. Any other issues with timing chain to do or concerns. This is step that I believe will be the hardest and most difficult.

Thanks again,

Eric

[Hijacker]

The service manual will tell you not to pull the chain when you lift the head, That's doable, but I always worry about the chain skipping a tooth on the crank. If the motor is out of the car, I'll pull the chain as well for peace of mind. If you're doing this in the car, make sure to keep the chain tight while you remove the head. I use some form of weighting and let the chain hang over the side of the motor while I pull the head and prepare the block. Once you reassemble the head, set the cams per the FSM and the crank to TDC and count links if the colored links are rotated in the wrong orientation.

[IanS]

The service manual will tell you not to pull the chain when you lift the head, That's doable, but I always worry about the chain skipping a tooth on the crank. If the motor is out of the car, I'll pull the chain as well for peace of mind. If you're doing this in the car, make sure to keep the chain tight while you remove the head. I use some form of weighting and let the chain hang over the side of the motor while I pull the head and prepare the block. Once you reassemble the head, set the cams per the FSM and the crank to TDC and count links if the colored links are rotated in the wrong orientation.

Nissan is actually pretty smart with their chains. The lower covers have a baffle that is just close enough to the crank cog, and depending on motor, jack shaft cog, that will not allow the chain to shift teeth. As long as you set it to time, then mark the links that correspond with the marks on the cams, and reassemble in the same fashion, you will not lose time.

That being said, I always recommend a new chain and tensioner with HG jobs. If the headgasket failed, there could be any number of reasons, but most often, the mileage is high, and doing the chain, tensioner, and guides is a good idea. If you are taking it half way apart, why not replace it. I have done quite a few GA18 chains and HGs, they are very easy all things considered.

The last one I did gave me a bit of a scare. Did a HG, chain and all the stuff that goes along. Few thousands dollars worth of work. Car came back 2 months later with a blown motor. Seized, and with a hole in the block. The guy made it 19,000 miles and it still had the oil filter on it that I had installed, and my sticker in the window. Not a drop of oil in the crankcase. He said he just forgot to change it. Dumbass.

[eric zabin]

Hello FlatBlack and Hijacker,

Thank you for getting back to me. I am leaving engine in the car. The engine has low miles, so I just want to send the head to a machine shop and replace the head gasket. As per manuel, it sounds like I only need to remove upper cam sprockets and mark the chain and sprockets for reassembly.

Thanks,

Eric

[numbnuts240]

manuel knows his s***.

[sx moneypit]

manuel knows his s***.