I saw a sedan owner here do this and I did this now to mount an oil catch can to the timing cover but it doesn't fit because of the radiator shroud(I think people shave some of it off to make catch cans fit). There is also another way to do this using the DM2 method here in this thread. This is better and safer and it removes a lot more stuff. https://g35driver.com/forums/engine-...coolant+bypass Nissan has done this to make the cars emissions friendly. This has no adverse affect on the cooling capability of the car and it improves it instead.

This is only temporary for my car. I already have the coolant pipes ordered so I can weld them shut instead or tap and block them off with bolts like the DM2 bypass mod.

These caps are China made and even though they are thick I have no doubt that they will eventually burst after some time and lose someone a motor. That's why it's better to tap and weld the coolant pipes/flanges. The caps also seem to be rubber not silicone.

Anyone doing this make sure you have distilled water or extra coolant around. The only difference I noticed after doing this mod and bleeding the coolant system for more than 1 hour is that AC temp is a lot more precise now. Now there is a difference between 88F and 90F where as before I would have to go from 90F to 85 or 80F to feel a difference. I have no idea how and why this made an improvement.


Pics. Also the coolant system needs to be bled of air until the heat literally burns the skin at 90F 6"-8" away from the AC vents.

So what is the main purpose of this? Making your Ac more precisse?

as he stated above, he removed it to make his catch can fit. it also cleans it up a bit as far as appearance goes. nice write up!

Yes it is a nice write up....other that catch can, and cleaner look i see no point. But looks good ...BTW i cant wait to see the bypass kit installed..Good work!

great post. I wish I could get my hands on some nice silicon caps that would endure the prolonged pressure and heat. thanks Andrei

I did see some online some time ago but I do not remember where. I would give the caps on my car no more than 2 years of life expectancy on NA cars. FI less than 1.

really? I wonder how long a decent silicon cap would last. I'm skeptical about using the cheap caps and really dont want to weld and pressure test my line.

wait im confused. where is your fan? my fan is coming off the motor in the center of the timing cover. where is yours?

03s have it. 04+ don't because they have electrical fans. 04+ do have still have the pulley for the fan without the fan but I took the pulley off since it was there for nothing. Nothing wrong with the mechanical fan on 03s. It's old school vintage.

Silicone would be fine for a really long time as long as it's not cut by the clamps.

Found the silicone ones. I have this companies couplers on my car and forgot I bought caps from them 2 years ago. Highest quality you can buy. http://www.hosetechniques.com/svh-fi...aps-c-104_4_67

i have an o4 and i have the fan thats connected to the pulley

I had an 04 too before and it had electrical fans. Maybe early ones had it. Mine was 04.5 to be specific.

other than looking at the manufacture date is there anyway to tell which mine is? early or late model 04 that is

No other way. I think the date is on the plate on the front suspension tower.

ok just checked and yea mine is an early model 04. it was manufactured in august of 03