95 SC bit of a oil burning smell

[samstrader]

Thanks Previologist. I'll drive for a couple of weeks and check the tray for oil. I cleaned it real good when I changed my valve cover gasket. I hope changing the valve cover gasket will stop oil under the distributor. I did have a valve cover oil leak on the vertical front valve cover seam and that oil was blowing backwards and some oil seemed to be buy passing the tray. I was also getting a drip of oil on the number one exhaust tube from the front part of the valve cover and this was causing a burned oil smell.

I have put a piece of sheet metal under the metal plate under the distributor to direct any oil drips away from the exhaust collector so I don't get oil burning smells her from the distributor but the tray under the valve cover will still direct oil to the exhaust collector. The problem I have with oil dripping out of the distributor is oil drips on my garage floor.

I hope changing the valve cover will stop what I am thinking is the distributor leak. If it doesn't, I plan to change the "O' ring under the distributor again and this time I'll use a genuine Toyota part. Last time I used a Fel-Pro "o" ring.

I never have changed the "O" ring and the valve cover gasket at the same time but I will in the future.

[samstrader]

Hi TBkilb01, It took me a minute but I finally can see the modification you made to the drip tray. How did you connect the tube to the tray so the oil will drip down the tube you installed? That's a good idea. I've thought of putting some kind of diverter like you did but have not figured out how to connect it to the tray.

I wonder why Toyota didn't do something like this instead of intentionally dripping oil on the exhaust system. I guess they figured if you smelled oil burning you would get it fixed.

[tbkilb01]

I often use the “advanced search” words up in corner, they are just below the search bar
...to find stuff...kinda small letters but have big results!
I typed ...burning oil
There’s a write up on it that pops up.
but yea, I was just winding up the gasket job that year and decided to clean things up a bit when I thought to form and JBWeld a copper line to the tray to divert oil that collects on the tray from ending dripping and ending up burning on exhaust. I may have modified the tray to accept the tube using a craft saw...oops sorry Previa...I haven’t smelled any burning oil lately, at least not from that spot! But that’s a good thing... I too did the dizzy gasket at that same time...

Im currently going after the brakes system and then moving to changing all fluids and then the front main seal..
.I’m hoping to get ole bloo roadworthy here shortly...
Allot of valuable info here on
.........................TOTOYAVANTECH..........

[tbkilb01]

I never have changed the "O" ring and the valve cover gasket at the same time but I will in the future.

Changing those items together with a lil cleaning
will solve allot and
give allot
of peace of mind
get er done..........

[samstrader]

Thanks tbkilb01,

I just learned how to use the advanced search a couple of weeks ago. If you look at the tag list, it will show you the words to put into the advanced search. I'll find the burning oil post.

good luck on your front seal gasket. I changed mine when I replaced my water pump. It's hard to get the harmonic balancer off. I had to heat up the bolt holding it in in order to get it loose. I had to heat it up to red hot with an acetylene torch. I hope yours comes off easy.

[samstrader]

I just used advanced search to find your 2015 post on the tray modification. Very nice job. I wonder why Toyota made the tray drip on the exhaust header. They must have had a reason.

You could even run your copper tubing to some kind of collector to catch the oil instead of letting it drip on the ground. No rags but a small can or something. Anyway, a clever way to fix a problem.

[tbkilb01]

That’s great really great........
plan is not to have any drips
if I see a drip on driveway ... then I’ll address... but no leaks so far anymore...it was a mess before repair for sure...
yea luck... bloodog looks pretty good underneath... usually a good spray of tranny fluid and blaster fluid loosens nuts and bolts pretty consistent...
but one never knows ...
..till you get a wrench on it...
have fun ....drive Previa

[cb97alltrac]

I recently changed the valve cover gasket and also the dist o ring at the same time. There is now no sign of oil in the trough below the vcg. But there still is a small amount of oil that is coming from the dist that collects on that small metal tray below it. Van runs fine with no oil burning small so not a big deal at this time. Must be another oring around the shaft. Will check the dist bolts to make sure they are tight. It's possible I may have forgotten to tighten one down. Did not use blue loctite.
Front end noise when going over bumps turned out to be a loose sway bar link on the passenger side. Nut did not have nylon on it or blue locktite and it almost come all the way off!

[Previologist]

Must be another oring around the shaft.

I have never done that job but I believe there is.

[pdgizwiz]

I don't believe there are two O-rings. Here's the diagram from my '97 FSM:
Previa-dist-exp.jpg
Previa-dist-ORing.jpg



The part labeled "packing" is a dust seal. There shouldn't be any oil inside the cap. If oil is still leaking by a new O-ring, and the O-ring itself isn't damaged in some way, it may be due to scoring in the surfaces that the O-ring contacts (either in the groove of the distributor body or the bore in the rear intake cam cap/cylinder head). And although the mating surfaces of the cam journal cap and cylinder head are machined to a fine finish, I apply a tiny bead of Permatex #3 between them as insurance that oil doesn't leak through that junction.
Still, any such leak would be negligible compared to that of a failed valve cover gasket or distributor O-ring. I figure any 25+ year-old car can be excused for a bit of seepage here and there, if regularly monitored.

There may well be a seal of some sort buried in the "distributor housing assembly" but I have never seen one leak there or tried to take one apart. If there is a significant leak there, I'd probably try to find a replacement.

[Previologist]

I don't believe there are two O-rings. Here's the diagram from my '97 FSM:

Diagram isn't showing up but what I meant was if he didn't change the one on the shaft, he isn't done.

[pdgizwiz]

I've edited my message, and hope the pics show up now. It's been a while since I posted here and had to figure it out all over again!

[samstrader]

I recently changed the valve cover gasket and also the dist o ring at the same time. There is now no sign of oil in the trough below the vcg. But there still is a small amount of oil that is coming from the dist that collects on that small metal tray below it. Van runs fine with no oil burning small so not a big deal at this time. Must be another oring around the shaft. Will check the dist bolts to make sure they are tight. It's possible I may have forgotten to tighten one down.

My leak condition is exactly the same as you describe for yours. I've always thought there must be some kind of seal on the distributor shaft. I just saw PDGIZWIZ post with the FSM drawings showing the second O Ring shaft seal. I have never seen that seal but I'm sure this is what is wrong with mine. I'll ask PDGIZWIZ for the part number or place to get an after market O Ring that fits this shaft.

Thanks for your help...

Sam

[samstrader]

Thank you PDGIZWIZ for the two diagrams from the FSM. I have never known about the shaft O Ring but I'm sure this is what is wrong with my car. This is so good to know because I've been trying to figure this out for a lot of years.

Thank you also Previologist for commenting about the shaft O Ring too.

Do you know the part number for the distributor shaft O Ring or do you know how to get an aftermarket O Ring that will fit the shaft. I've never seen these parts listed anywhere.

Thanks again for your help. I have been looking for this answer for 20 years.

Sam

[pdgizwiz]

The distributor O-ring is part number 90099-14091

[samstrader]

Thanks again PDGIZWIZ... The picture you posted with the distributor on top of the picture and the distributor gear with the hand on it on the bottom of the picture just posted real good and I can see it better. The O Ring part number 90099-14091 is the distributor mounting O Ring. You put that on when you are ready to push the distributor back in the hole. I've changed this one a few times.

I think I'm understanding incorrectly but I thought based on the picture with the guys hand that there was also an O Ring on the shaft just behind the gear. And I was thinking replacing an O Ring here would stop the oil leak I have that is getting oil inside the distributor cap. But I think I'm seeing this wrong and now think there is just one O Ring that seals the distributor when it is mounted.

Tim said in another post that sometimes oil leaks from around the shaft of the distributor but when this happens the engine runs rough. That would mean to me that the bushing or whatever supports the distributor shaft is worn and the shaft is wabbling... But my engine is not running rough. So I'm wondering what to do to stop the oil leak that is leaking oil into the inside of the distributor cap. I think people are saying you just need to replace the distributor when this happens. Is this correct?

I have another question that I've always been curious about. What is the purpose of the two short hoses that are connected to the distributor. I used to think they were cooling water hoses but don't think that now since they are never very hot.

Thanks for all of your help. It's getting pretty hard to get parts and information for my car now. I broke the clip that holds the hood rod up when the hood is down and went to the local dealership to get on and they laughed at me.... I had the part number and they were able to order one and it is sure better than the ultra hard 32 year old clip was. But it is not too easy to get parts anymore.

[pdgizwiz]

samstrader:

"I think people are saying you just need to replace the distributor when this happens. Is this correct?"

Yes. The "distributor housing assembly" with the rotating parts and the base of the distributor isn't designed to be disassembled, so if the bushing (and possibly a seal) in it is worn to the point of wobbling, it is likely to leak oil as well. I've never seen one in this condition, but it's reasonable to expect that it could happen in a van that had seen a lot of miles.

"What is the purpose of the two short hoses that are connected to the distributor. I used to think they were cooling water hoses but don't think that now since they are never very hot."

Good question. As you found, these hoses don't carry cooling water, but since there are two of them it's reasonable to imagine that they carry warm air out and cool air in. Since the distributor is just above the exhaust manifold, Toyota's engineers must have been concerned about the distributor getting too hot. The heat shield on the bottom blocks some of the heat being radiated by the manifold, but passing cool air through the housing could help protect the internal parts. Later engines have no distributor at all, but the Previa engine had not evolved to this point - at least not those sold in the US.
It's sad that your dealer laughed at you. I have replaced that plastic hood-prop clip myself. We live in a 'throw-away' culture and they shamed you for wanting to maintain your van. The auto manufacturers want us all to buy new cars every few years. I have found Toyota better than most at making parts available for their older models, but since Previas are around 30 years old now, it is becoming more and more of a challenge. Those crazy-long wiper blades are a good example!

[samstrader]

Thanks again for your help pdgizwiz. I think I finally understand the whole distributor issue and it's good for me that I understand now. I feel better about it all. Since I have changed the valve cover gasket and the distributor O Ring, my oil leak is very small so not much of a concern really but I wanted to fix it.

I just used the last of my Toyota A700 wiper blade inserts this year. I saw a video somewhere on how to use other inserts to replace them and plan to try that method when the next replacement time comes.

I sure appreciate your help...

Sam

[pdgizwiz]

There's an earlier thread about replacing a bearing and seal in the distributor housing.
I found a similar but more detailed thread on a different forum for a different model of Toyota.

It looks like the Previa distributor is easier to get apart than the other. I expect other details are similar, but I haven't been down either road so I'm just guessing.
In either case, ball bearings used are normally of standard sizes. Seals are too, since they often mate up with bearings. Both are manufactured in enormous quantities for the economy of scale.
As our vans age, this info might become more useful.

[samstrader]

Wow... How nice is this thread that you found. This is just what I needed to know. It is so good to see what is in there so you can understand how it works and what needs to be changed.

Thanks for finding this and sharing it...