Ive read and re-read multiple posts about the power valve screws issue on the VQ engines and am concerned and am planning to DIY to fix this issue. Hopefully, nothings happened and it will be a preventative thing. I do have low power and sluggish acceleration and am wondering if its got anything to do with anything as I cant figure it out. The acceleration is slightly better than my 00 Q with a 3.3 but still not as good as I expected and certainly not smooth as the 3.3. The 3.5 with 80k is rougher sounding and riding than the 3.3 with 126k. I have new air filter, oil filter, oil and everything looks ok.
Anyways, 1) I was wondering, does one need any special tools for this job or will my regular toolbox do? 2) Would you recommend this as a DIY for a novice? Ive only done oil changes and changed belts, plugs (on easier cars), put on an alternator and a radiator etc but nothing major so far. 3) Anything in particular that I should be careful about? Not unhooking a cable, or not reusing a gasket or a bolt , applying a sealant where applicable etc?
Ive printed out the excellent help from Bowtied(also a sticky at the top here)http://npora.ipbhost.com//inde...17104
Ive also printed out the following pics here;http://davejohn.home.insightbb...x.htm#
I went to the Nissan dealership and they stated that in the last 15 yrs they have never heard of such an issue!! And then add that there was indeed a recall for this issue but only for the 04 and 05 Maximas and Altimas. They said theyd still do it for me but for 500 bucks!! I thanked them and left as I felt that that was just way too much.
I was wondering, is it the same labour and work involved in changing the spark plugs? If so, I know a good mechanic who could do it for a good price and while hes reached that point, maybe he could also loctite the power valve screws? Or would it need more work of unhooking, dismantling etc? I havent studied the prints yet and will be doing so today. Am planning to attempt this this week.
Also, does anyone have or could suggest where I could find the 02 QX4 FSM?
I am contemplating replacing the valve cover and replacing the PCV valve as well as I think I may be burning oil and there are no leaks and have read that this is due to yet another design flaw in that the baffles are poorly designed and some of the oil is sucked out through the PCV vavle.
Any help, advice and suggestions on the above would be greatly appreciated. Im a novice with only an aptitude towards this kind of work.
Attempting to loctite the power valve screws- 02 qx4. Help please...
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Pwnin O'Brien
- Posts: 1612
- Joined: Wed Jun 24, 2009 1:10 pm
Re: Attempting to loctite the power valve screws- 02 q ... (ugharin)
As far as the butterfly valve screws, the job is pretty simple and straightforward. If you've changed the spark plugs on a VQ then you should have no problem checking the butterfly valves. The only special tool you may need is a socket elbow to reach the bracket on the intake manifold on the passenger side between the manifold and the firewall. Other than that you just need sockets, screwdrivers and a torque wrench. You may want to to get some gasket maker for the throttle body if you get any unexpected leaks, but that should already be in your toolbox. You may want to pre-purchase any gaskets you will need to remove for the job. You will probably be able to re-use a few gaskets, but it's cheap insurance to just replace the gaskets; the cheapest way would be to order the necessary gaskets online (like from CourtesyParts).
The butterfly screw issue really isn't as prevalent as you read about on the internet. The reason it's so talked about on forums is because that's the first place people go to look before taking the vehicle to the dealer. Since I've been a member on NICO (a little over 6mos.) I've never once heard of anybody having this issue (besides reading the sticky and such). I would say that if the screws haven't backed themselves out in 8 years, they probably won't at all, but it's a piece of mind thing.
You might as well replace the PCV valve since you'll have to take the upper intake manifold off to do the butterfly valves anyhow. The thing about burning oil is that there is only one known fix to the problem. That fix is to install an inline catch-can to catch any oil before it gets sucked back into the engine. The problem is that the VQ valve covers have a horrible design in that they collect oil when they shouldn't. The design in the valve cover is supposed to prevent the PCV from sucking any oil spatter into the intake, but it collect the oil instead. If there are contaminants in the oil, then they build up in the valve cover and clog the PCV.
Replacing the valve cover gaskets are pretty involved and require more work than just removing the upper intake manifold. If you are that adamant about replacing the gaskets, then I would recommend cleaning the valve cover and make sure the PCV isn't being clogged.
The 3.5L VQ engine is a very loud engine on the interior of the vehicle. Even before I added my K&N FIPK it was noticeably louder than my moms 4.0L 4Runner; it was actually more than twice as loud.
The butterfly screw issue really isn't as prevalent as you read about on the internet. The reason it's so talked about on forums is because that's the first place people go to look before taking the vehicle to the dealer. Since I've been a member on NICO (a little over 6mos.) I've never once heard of anybody having this issue (besides reading the sticky and such). I would say that if the screws haven't backed themselves out in 8 years, they probably won't at all, but it's a piece of mind thing.
You might as well replace the PCV valve since you'll have to take the upper intake manifold off to do the butterfly valves anyhow. The thing about burning oil is that there is only one known fix to the problem. That fix is to install an inline catch-can to catch any oil before it gets sucked back into the engine. The problem is that the VQ valve covers have a horrible design in that they collect oil when they shouldn't. The design in the valve cover is supposed to prevent the PCV from sucking any oil spatter into the intake, but it collect the oil instead. If there are contaminants in the oil, then they build up in the valve cover and clog the PCV.
Replacing the valve cover gaskets are pretty involved and require more work than just removing the upper intake manifold. If you are that adamant about replacing the gaskets, then I would recommend cleaning the valve cover and make sure the PCV isn't being clogged.
The 3.5L VQ engine is a very loud engine on the interior of the vehicle. Even before I added my K&N FIPK it was noticeably louder than my moms 4.0L 4Runner; it was actually more than twice as loud.
Re: Attempting to loctite the power valve screws- 02 q ... (Pwnin O'Brien)
Hi Pwnin and thanks for the detailed reply.
I will get the gaskets and also the elbow socket.
So, other than the gaskets, everything else is dissemble and assemble. No particular attention required anywhere..Am I correct? Maybe clean something up while there or apply a sealant or something? Never been there done that..
I really would like to do this for the peace of mind. Although its an 8 year old car, it only has 80k miles. A lot of posts I read had this (screws ingestion) happen even after 100k or 120k miles. Dont want to take a chance.
Any specific reason why you think they probably wont come off? Is this problem associated with any range of VINs or a percentage of vehicles or within a certain mileage limit or time limit?
Hmmm...about the inline catch-can, could you explain the fix a little better please? (novice here )
I did read that the drain hole is too small and the oil doesnt drain quickly enough and is meanwhile sucked out the PCV valve as well. How would the fix work out in here? I'll certainly go ahead and replace the PCV though.
The 02 seems to be running a little better the last couple of days after the oil change, air in tires and premium gas. With a compression of 10, I think premium/97 grade gas is required perhaps.
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Also, might be a stupid question but what exactly are these valves for? Can they be simply taken off? Do I have to replace the screws as well and use newer screws? How did Nissan remedy this problem?
Thanks again for the help.
I will get the gaskets and also the elbow socket.
So, other than the gaskets, everything else is dissemble and assemble. No particular attention required anywhere..Am I correct? Maybe clean something up while there or apply a sealant or something? Never been there done that..
I really would like to do this for the peace of mind. Although its an 8 year old car, it only has 80k miles. A lot of posts I read had this (screws ingestion) happen even after 100k or 120k miles. Dont want to take a chance.
Any specific reason why you think they probably wont come off? Is this problem associated with any range of VINs or a percentage of vehicles or within a certain mileage limit or time limit?
Hmmm...about the inline catch-can, could you explain the fix a little better please? (novice here )
I did read that the drain hole is too small and the oil doesnt drain quickly enough and is meanwhile sucked out the PCV valve as well. How would the fix work out in here? I'll certainly go ahead and replace the PCV though.
The 02 seems to be running a little better the last couple of days after the oil change, air in tires and premium gas. With a compression of 10, I think premium/97 grade gas is required perhaps.
--------------------------
Also, might be a stupid question but what exactly are these valves for? Can they be simply taken off? Do I have to replace the screws as well and use newer screws? How did Nissan remedy this problem?
Thanks again for the help.