3.4 toyota sludge prone or no?

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Hey everyone,

I've got a '97 Tacoma with the 5vzfe. 253k on the original engine and I know it's had a rough life. Peering into the valve cover you can see some minor sludging it looks like.

Are 3.4s more susceptible to sludging with extended OCIs and conventional oil? I would like to run 8k OCI, as I drive all highway 70 miles per day.

Right now I'm running semi syn valvoline 5w30.
Thanks yall
 
No, I just finished doing my valve cover gaskets on my 3.4 and no sludge at all. The fill hole is NOT a good indicator of the rest of the engine. Also these are not known to sludge but if you have a leak it is most likely the valve covers and it is a easy but long job. Congrats on getting the most reliable engine (non diesel) ever.
 
Sludge or varnish? The latter is pretty harmless. If it's sludge, most modern synthetics will do a good job of slowly cleaning it with 5k changes. Of course you can run 8k, just don't expect the sludge change much. As long as it's not chunky, it's probably harmless.
 
Also personally I would not run a semi synthetic that long in this engine. I believe OEM was 3k on conventional. If you suspect neglect then run a few short OCI and then run a synthetic for 10k miles.
 
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The 3.4 in my experiences have been extremely clean engine. I have owned multiple Tacomas as well as a 4Runner all with the 3.4. In addition it didn't seem to care what oil you put in them. I really liked the 3.4 motor and that motor should far outlast anything on that truck...my biggest concern with the the Tacoma is frame rust.
 
Originally Posted By: Oey12
The 3.4 in my experiences have been extremely clean engine......

Ditto. 3.4L timing belt engine very easy on oil, reliable and no sludger ime. Don't be fooled by the valve cover baffle at the fill hole that can be misleading, not an indication of valvetrain appearance and condition.

As for Tacoma frame rust, ime very location specific. Very little salt used here so no worries on an 01. Some were repurchased by Toyota in northern climes.
 
Yep--the baffle under the fill cap holds a little oil that sludges up but thats not indicative of whats beneath.

The maintenance interval in my little booklet shows 5k for severe service (towing, dusty, etc.) and 7.5k for normal conditions. I just stick w/ ~5k no matter what (hot weather, lots of hwy miles)--clean oil is cheap insurance. After I got my gaskets and seals changed out I use nothing in a 5-6k interval.
 
Originally Posted By: leemajors
Yep--the baffle under the fill cap holds a little oil that sludges up but thats not indicative of whats beneath.

If it looks like this:




Then that's not sludging at all, it is how the baffle is supposed to look (it is a coating). On a lot of older Toyota engines you cannot see the engine internals through the fill hole, you have to remove the valve cover to see anything.
 
On the 5vz-fe it looks a little different--you can see past it a little bit. Mine has a bit of crustiness on it that isn't consistent so it doesn't appear to be a coating. I just always assumed it was some oil that was trapped behind it from spinning cams and the heat cycles had sludged it a bit.

Either way, I'm agreeing with you that it's almost impossible to judge sludge from the 5vz-fe fill cap.

Edit:

Here's mine at least. You can see varnish underneath and the crust just looks like captive sludge. Either way, no big deal.

 
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Originally Posted By: spencerdiesel
Hey everyone,

I've got a '97 Tacoma with the 5vzfe. 253k on the original engine and I know it's had a rough life. Peering into the valve cover you can see some minor sludging it looks like.

Are 3.4s more susceptible to sludging with extended OCIs and conventional oil? I would like to run 8k OCI, as I drive all highway 70 miles per day.

Right now I'm running semi syn valvoline 5w30.
Thanks yall
Mind posting a picture of what you see under the valve cover? Anyone can do it. You can even upload pictures to this website.
 
Lot of informative responses. I feel better now, leemajors mine looks very similar to your pics you posted. TheKraken, why do you not recommend running 8k on the syn blend?

Keep the talk coming
 
I've got a 3.4 in my 97 4runner with 300+k, and my oil doesn't even change color until about 4k into each OCI (I run dino Pennzoil 5w30 HM - have never put synthetic in her). OCI i tend to 6 or 7k. Like someone said above, rust is the real issue. Valve cover gaskets and rear main like to leak oil, but I still haven't replaced mine yet (just tighten the valve covers down once a year or so).
 
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Originally Posted By: spencerdiesel
Lot of informative responses. I feel better now, leemajors mine looks very similar to your pics you posted. TheKraken, why do you not recommend running 8k on the syn blend?

Keep the talk coming

If it looks like Lee Majors' picture, then I'd propose that what you saw is mere varnish, which is unsightly but functionally not harmful.
Therefore, no cause for concern, in my opinion.
 
Well I've got about 6k on 5w30 maxlife right now. I was going to change it and send a sample in at 7 or 8k. with my driving conditions and this engine being easy on oil, Y'all feel it'd be alright to run 7 to 8k? I know the maxlife is kind of lower on the TBN pole right?

With 257k and frame rust (anyone know if the frame recall is over with?) i don't think the engine will be dumping before the rest of the truck whether I run 8k or 12k.....

Thoughts?
 
Not sludge, but I think the 3.4L is known to blow head gaskets. So maybe coolant is getting into the oil and sludging?
 
Originally Posted By: Nick1994
Not sludge, but I think the 3.4L is known to blow head gaskets. So maybe coolant is getting into the oil and sludging?
\

3vz fe (3.0) is known to blow head gaskets. Not the 3.4 (5vz fe). Absolutely amazing motor and pretty easy to work on. Doesn't mean its not possible but not a known issue.

OP, if you want to run the oil 8-10k go for it. I am sure the oil is good for it. I personally run 5k OCI on my 3.4 but it is not rusting to [censored] and I plan to own it for a long while.
 
Originally Posted By: TheKracken
Originally Posted By: Nick1994
Not sludge, but I think the 3.4L is known to blow head gaskets. So maybe coolant is getting into the oil and sludging?
\

3vz fe (3.0) is known to blow head gaskets. Not the 3.4 (5vz fe). Absolutely amazing motor and pretty easy to work on. Doesn't mean its not possible but not a known issue.

OP, if you want to run the oil 8-10k go for it. I am sure the oil is good for it. I personally run 5k OCI on my 3.4 but it is not rusting to [censored] and I plan to own it for a long while.
Oooh ok, had them backwards.
 
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