MarineE6

Leaking Valve Cover Gaskets

24 posts in this topic

Hey Guys

Newbie here! I got a 98 626 2.5 v6 DOHC. Both Gaskets are leaking. I was wondering if I should replace all gaskets I come across, or hold fast to the cliche' "if it aint broke don't fix it". If I do need to replace anything, can anyone lead me to a good price on a gasket set or what not. If I can avoid replaceing anything other than the VCG, how can I tell if other gaskets need replaceing. Been fixing my own cars since I started driving , and being 29y I have had everything from CV joints to Oil Changes(brakes are in there somewhere and one VCG without the 626 mess on the back VC, LOL). I don't know how long the car was sitting on the lot before I bought it in 2010. But, the word was that the owner babied it. The dealer is a well trusted guy, so I believe him to a certain extent. Oh, and before I forget, can anyone give me a time estimate on a DIY job. Thanks guys!

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You can get a set from RockAuto. If you're valve cover gaskets are leaking then they are broke so that cliche' doesn't hold up. Broken valve cover gaskets means the PCV system might not work properly. As long as it's a minor leak probably nothing to be concerned about but you do want to get them fixed.

http://www.rockauto....&parttype=10710

Welcome to Mazda626.net MarineE6!

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I got these, seem to work just fine(also used black rtv sealant): http://www.ebay.com/...=item3f05f27943

Did it in a few hours, so it's not very difficult, just make sure you don't break any vaccum hoses/fittings when pulling off the intake manifold, also don't overtighten bolts as they break too easily.

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Took a while to find this thread because you posted in another one and someone moved it I guess.

I think you misunderstood DJ. He meant as in any other gasket he comes across (throttle body gasket or intake manifold gasket) if he should replace them.

I'd personally get the other gaskets. Most likely, the throttle body gasket will tear. I'd also get the intake manifold gasket since those are metal. I'd definitely replace as much as you can, possibly going as far as the camshaft seals (maybe too advanced). I agree with "If it ain't broke, don't fix it", but what you would be doing is preventative maintenance. I don't remember what other gaskets, if any, you run in to. I do have the factory service manual, so if you need any detailed instructions I can provide them.

Welcome to the forum!

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Oh duh you're right. Sorry. Definitely the throttle body gasket. I've replaced 2 in the past 8 years.

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But, the word was that the owner babied it. The dealer is a well trusted guy, so I believe him to a certain extent. Oh, and before I forget, can anyone give me a time estimate on a DIY job. Thanks guys!

It wouldn't matter if he babied it or not, as every KL I've ever come across in the junk yard has a leaking front VCG. I didn't check the rears, but that gives you an indication that it's sort of common. I have a running joke with my friends that all Mazdas either leak or burn oil, but at least they're consistent, lol. ;)

I wouldn't know what to tell you for a time estimate. I haven't done a VCG replacement on the KL, but I work super slow and check everything about 3 times. I've had many 45 minute jobs turn into a week, though, between waiting for parts I didn't know I'd need, etc. Just be prepared, and don't rip into it a 9pm the night before you have to go to work.

And welcome to the forum!

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I just did my rear vcg about a week ago and i had about six hours with a trip to get tb cleaner and egr cleaning (which i recommend) thrown in.

I suspect the front will take another hour.

Mine's an '02 and if yours is the same, ....

There are thirteen main bolts holding the intake on. The thirteenth is the upper of two on a bracket in the rear driver's side which is invisible...i think i used a 12mm deepwell socket on a 3/8 drive ratchet and it wasn't too bad once i found it.

Keep track of all those hoses and connectors!!Here's a few pics I snapped with my phone while I was in there if you're interested.... http://s534.photobucket.com/albums/ee346/3dman7/2002%20626%20Rear%20VCG-egr%20project/

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Let me put this out there...... if you have any oil leak from any gasket, 9 times out of 10 it was caused by a bad PCV valve. If you change your VCG's, then please change the PCV as well. I have had the same VCG's on my motor since I bought the motor back in '06 and it has been doing just fine because of me constantly changing the pcv.

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Does the valve just clog up and force it out the VCG? All of the leaking I've seen has been right on the front by the rad.

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WOW Thanks Guys! I appreciate the responses. I am the big picture type so your pics and advice are going to go a long way for me! I will keep you posted!

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No problem. I'm very visual, also, so I know where you're coming from. My friends and I draw pictures when we're describing things. :P

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I have a brand new valve cover gasket for sale if you need it. $15 felpro. Car died before I could install it. Let me know

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PrinceV and blackshine, I checked my PCV. What you guys were saying could make some sense to why my VCG are already going out. They weren't as bad as they are now when I bought the car but I saw that I would need to get it done. Didn't get a chance to really look at it but I think I will take the time to get it changed any way.

Hant, I really appreciate it. Is it front or back? For 15 bucks I have a feeling you are just talking about one. Either way, if you can let me know I can make a decison on what I am going to do.

Thanks Guys, I am very gald this forum is alive and well. Great Minds think alike, Right. Very Grateful for all of the Responses and Warm welcomes.

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I'm not sure how mechanically inclined you are, but I scan the pages of the service manual that will show you step by step on how to change the valve cover gaskets.

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Xeno, Yes that would be very cool. To give back, I was planning on doing a step by step photo thread to change these VCG buggers. Hopefully if I can get to it before it gets cold I should have it up before the end of the year. Money, unfortunately hinders this process. I'm NOT making any promises on the time frame, but I do want to have a Photo thread dedicated to this painstaking process. Thanks Again.

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It really isn't that bad. I did it not too long ago and you'll find a lot of vehicles are similar. I will mention be careful with the VCIS. I ended up breaking the plastic nipple that a rubber hose was attached to (under the intake manifold). I used Q-Bond (great stuff btw) to fix it, so not all was lost.

I'll scan the pages real quick when I get home.

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Awesome, my biggest thought was to watchout for that vacume tube also under the Manifold. Other than that my confidence is building day by day. It should be just as easy as the Nissan I did a couple of years ago. Tedious but very easy now that I look back.

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yea. its not a bad job to do in all truth. it just seems like alot more then it is. the hardest part is getting the invisible bolt on the backside. and even that isnt that bad as long as you know its there, and about where its at.

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More how to articles with good pictures are ALWAYS wanted. If you want to contribute back that is an excellent way of doing it.

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When the valve cover gaskets dry up and start leaking on the 2.5 L v-6, they also fill up the plug holes with oil so u might as well replace the gaskets and the plugs/wires. I just did it on my 98 ES V-6 and all six of the plug holes were full of oil.bj

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Thanks bj23, I was looking at them my self and saw some innocent spots. As long as I change the VCG's very soon I should be fine. The wiring is gonna add to my pocket book more than I need right now. With checking out others advice I went ahead and checked but they seem to be safe, for now(knock on wood). Thanks for the heads up!

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PrinceV and blackshine, I checked my PCV. What you guys were saying could make some sense to why my VCG are already going out. They weren't as bad as they are now when I bought the car but I saw that I would need to get it done. Didn't get a chance to really look at it but I think I will take the time to get it changed any way.

Hant, I really appreciate it. Is it front or back? For 15 bucks I have a feeling you are just talking about one. Either way, if you can let me know I can make a decison on what I am going to do.

Thanks Guys, I am very gald this forum is alive and well. Great Minds think alike, Right. Very Grateful for all of the Responses and Warm welcomes.

Hi Marine E6. Sorry for the delayed response. Been busy busy with my research at school. Anyways, the gasket is for the rear. If you want it, just let me know. I am in Buffalo NY. Not too sure how much it cost. Let me know.

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Well I used the Blue RTV Gasket Maker. It's great and has been so far. I hated paying $32 for an actual gasket when a tube of that was only $7. Mine is an I4 so time consumption will be less then yours but non-the-less everything needs to take time.

This site has been great for me cause there is more information on these cars here then anywhere I have looked before. Everyone here is very hospitable and willing to help in almost every way. Welcome and enjoy :D

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Depending on the mileage you may want to replace or clean other parts while you have everything torn apart. In particular I would clean the throttle body, EGR and the port that leads to the EGR from the intake manifold. Its not uncommon for this to clog and cause a CEL(P0400) on high mileage cars. The PCV valve was already mentioned. I replaced all gaskets I came across, except the little metal EGR gasket. There were a couple of coolant hoses that were replaced, the haynes manual suggests the one that runs under the IM. There were two back behind the engine that went into the firewall that I also replaced. I also put in a new fuel filter and thermostat since those were due for replacing.

Dunno if my 99 has fared better then most, but it doesn't leak or burn much oil. At least its never needed to have oil added between the 5K oil changes. My front VCG started seeping a lot sooner then the rear. I think it was around 150K that it was replaced. The rear VCG held up till 180K, then I had oil getting into just one of the wells. It stayed that way till 190K then I replaced both of them. Make sure your VCG set comes with all of the grommets. My first one only came with enough grommets to do one VCG =/

edit: Would just like to add, that I would replace the spark plugs unless they are recently new. The wiring I wouldn't bother with unless it is worn or damaged. I know my car is still using its original wire set.

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