Take it down to the heads or just valve covers

[G_Raw]

I've been putting off my valve covers for too long. Both are seeping something ugly. Of course cam plugs, half moons, pcv, plugs, wires, etc will get done at the same time. My question is at that point if I take the timing belt etc off which isn't much more work I can take more things apart and do the heads, timing belt, exhaust gaskets, water pump etc, back up to those valve covers.

I have 225k on the engine and no knowledge of the last time these things were changed.

With that said I'm questioning going down to the heads because I get some white clouds on cold start that goes away once warmed up. Makes me think coolant is sitting in a cylinder then gets burned off. Which is the start of a failed head gasket. I doubt it's a cracked head since it stops once warmed up.

I started the truck up with rad cap off and no bubbles...So maybe the white cloud is heavy steam in the cold wet bay area air?


How would you proceed? Just do the valve covers since I know they are leaking horrible? Tear the whole block down and build back up? Drive it as is and prepare to buy a 4x4 4runner? ( mines 2wd but it's been in the family since day 1)

Side note...anyone use gasket kits for 5vz from yota shop? Or just spend money on OEM the whole way?


COVID 19 has given me some free time to do such a project.

 

[Adamdmc]

I recently did all of that to my engine. Really not much more in parts to replace head gaskets. Especially if your valve lash measures in spec. It really is a great way to get to know your engine. Only thing that I wish that I would have been told was to go back after a few good engine warm ups, say 500 miles, and retorque your valve cover bolts. After 4k miles I freaked out a little when mine were leaking again. Good wrenching and keep us posted.

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[rideexileex]

I've been putting off my valve covers for too long. Both are seeping something ugly. Of course cam plugs, half moons, pcv, plugs, wires, etc will get done at the same time. My question is at that point if I take the timing belt etc off which isn't much more work I can take more things apart and do the heads, timing belt, exhaust gaskets, water pump etc, back up to those valve covers.

I have 225k on the engine and no knowledge of the last time these things were changed.

With that said I'm questioning going down to the heads because I get some white clouds on cold start that goes away once warmed up. Makes me think coolant is sitting in a cylinder then gets burned off. Which is the start of a failed head gasket. I doubt it's a cracked head since it stops once warmed up.

I started the truck up with rad cap off and no bubbles...So maybe the white cloud is heavy steam in the cold wet bay area air?


How would you proceed? Just do the valve covers since I know they are leaking horrible? Tear the whole block down and build back up? Drive it as is and prepare to buy a 4x4 4runner? ( mines 2wd but it's been in the family since day 1)

Side note...anyone use gasket kits for 5vz from yota shop? Or just spend money on OEM the whole way?


COVID 19 has given me some free time to do such a project.

I'd say take a whiff of the exhaust and determine if you can smell the coolant. OEM for the headgasket would give me the most peace of mind, especially after all the involved labor, but I think for all the valve cover gaskets, etc, they're all quite similar. RockAuto FTW.

Headgaskets on this engine are a pain, and require a good variety of tools to access all of the different bolts, studs, nuts, etc. The exhaust nuts/studs have always been the biggest pain, and several of the them have broken on me in the past. Definitely pre-soak (a lot!!!) them if doing this while the engine is in!

 

[JohnMc]

A little white steam out the exhaust on a cold start-up is NOT a sign of a HG starting to fail. The two main things produced by burning gasoline (a hydrocarbon) is CO2 and H20. If the exhaust system is cool, it can help the superheated steam in the exhaust cool down and form visible steam. When the exhaust system warms up - the steam doesn't condense before dissipating.

That said - you will be a lot of the way down to getting the heads off with the top end and front end of the motor apart. 85% of the labor already done? Or close. And the 5VZ is an iron block with aluminum heads, those tend to creep against each other as the engine warms up, which can eventually lead to HG failure after a long while. I think Toyota went through 4(?) revisions of the HG style from 96 on. The original being a mostly conventional composite HG. Followed by iterations with more and more metal cladding covering up parts of the composite, end finally ending up with full MLS style all metal gaskets. I think the earlier styles are somewhat prone to failure - and IIRC there was a recall on some 96 production engines.

I could be wrong, but I think the 99's came with the 3rd revision, not the (maybe) bulletproof final version. Normally I'd say just wait until the issue arises to deal with it, but when you're almost all the way anyhow? Maybe give it a go. And use the latest style gaskets.

My wife had a HG go on her '96 a couple of years ago. On disasssembly it appeared that two other cylinders were *almost* ready to fail (fire rings partly pushed out of the way). And it apparently had one of the later revisions - it was probably caught int he recall and had the original version 1.0 gasket replaced at some point. The HG failed at about 300K miles.

FWIW on her motor the cylinder bores still looked great. Cross-hatching still visible on 95% of the swept area - only some small shiny spots near the top on the sides of the bores. Should be good for another couple-hundred thousand miles now.

 

[UnderFire]

You are nowhere near 85% of the way there with just the valve covers off and I personally wouldn't do headgaskets unless they're necessary, because while doing a headgasket job you should have the heads hot-tanked, checked for cracks, decked, new valve seals and valve adjustment. In my area that is a $5-600 endeavor in itself.

Youve also got to take into account how much more needs to come off the get the heads off. Fuel system, exhaust manifolds and crossover, entire front dress, entire timing set, entire intake manifold, its no small feat compared to a simple valve cover job.

I'm not saying there would be no benefits, but it will easily quadruple the amount of time and money spent on the project.

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[G_Raw]

I'd say take a whiff of the exhaust and determine if you can smell the coolant.

A little white steam out the exhaust on a cold start-up is NOT a sign of a HG starting to fail. The two main things produced by burning gasoline (a hydrocarbon) is CO2 and H20. If the exhaust system is cool, it can help the superheated steam in the exhaust cool down and form visible steam. When the exhaust system warms up - the steam doesn't condense before dissipating.

I did smell the exhaust yesterday but smelt fine, like I said I couldn't replicate it at the time. I then realized since im thinking coolant is sitting in a chamber and gets burned off I'd need to make the engine burn it...So started up today normal steam, normal exhaust odor. Revved hard a few times and steam starts to change to noticeable white clouds blowing while holding revs. No white clouds when i stopped revving . Revved hard and high and went out to take a whiff and it smelt dare i say like a sweet spice? Cinnamon...ish?

I know doing my valve covers are no where near the heads, but I was going to do water pump and timing belt. And at that point I am close to my heads, and would need to redo all those upper gaskets anyways.

It's one of those do I spend 500 to do VC and timing vs 1200 to do VC, timing, and heads. Or worse do first option only to do second option a few months down the road...

 

[plcfcng]

If your going to do the head gaskets I would go ahead and be sure to have the valves cut and resurface the heads. The bill is about 500 in my area but it was worth it to me because the valves were out of spec. So to get a well sealed head and valves with properly adjusted valve lash it was worth it to me.:becky:

 

[19963.4lsr5]

The YotaShop head kit is the way to go. It even comes with valve stem seals.

If you’re going to do the timing belt it’s not much more to pull the heads.

I left the exhaust together when I replaced head gaskets on the puppy hauler. Just removed the manifold studs from the head.


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[phattyduck]

Don't pull the heads to do the headgasket until you have done more testing... compression, maybe leakdown, maybe put a borescope in the cylinders.

There is zero reason to do headgaskets before needed.

-Charlie

 

[UnderFire]

I did smell the exhaust yesterday but smelt fine, like I said I couldn't replicate it at the time. I then realized since im thinking coolant is sitting in a chamber and gets burned off I'd need to make the engine burn it...So started up today normal steam, normal exhaust odor. Revved hard a few times and steam starts to change to noticeable white clouds blowing while holding revs. No white clouds when i stopped revving . Revved hard and high and went out to take a whiff and it smelt dare i say like a sweet spice? Cinnamon...ish?

I know doing my valve covers are no where near the heads, but I was going to do water pump and timing belt. And at that point I am close to my heads, and would need to redo all those upper gaskets anyways.

It's one of those do I spend 500 to do VC and timing vs 1200 to do VC, timing, and heads. Or worse do first option only to do second option a few months down the road...

I've only had one vehicle do what you're describing with Coolant sitting in the cylinder and smoking on start up. It is very distinct. You'll notice a lot more symptoms than just a puff of smoke. First off it'll be slow to crank as it tries to compress the Coolant in the cylinder, second it will mix in with the oil giving it a white milky consistency, and third it will puff massive white clouds of smoke for more than a minute while running terribly until its able to burn off all the Coolant and water.

The small puff of white smoke that burns off quickly and seemingly doesn't affect the engine at all is perfectly normal especially when it's colder out and nothing to worry about as far as I'm concerned.

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[G_Raw]

I've only had one vehicle do what you're describing with Coolant sitting in the cylinder and smoking on start up. It is very distinct. You'll notice a lot more symptoms than just a puff of smoke. First off it'll be slow to crank as it tries to compress the Coolant in the cylinder, second it will mix in with the oil giving it a white milky consistency, and third it will puff massive white clouds of smoke for more than a minute while running terribly until its able to burn off all the Coolant and water.

The small puff of white smoke that burns off quickly and seemingly doesn't affect the engine at all is perfectly normal especially when it's colder out and nothing to worry about as far as I'm concerned.

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Trust me...by no means am I trying to go down to the head gaskets unless it is warranted. I've done a lot of fun mods this winter and now need to catch up on maintenence. Just don't want to ignore things that may kill my block. I want to join the 300k club.

The above post gives me hope. For piece of mind I'm picking up stuff to do a compression test tomorrow. If all passes I'll do the valve covers, then timing belt depending on days off.

I looked for the milky oil and don't see any. I'm also not losing coolant that I can tell. It's just weird to notice the white clouds now, I've been driving this truck for the past 5 years in my current area and never noticed the white clouds out the exhaust on cold start ups..

 

[19963.4lsr5]

Trust me...by no means am I trying to go down to the head gaskets unless it is warranted. I've done a lot of fun mods this winter and now need to catch up on maintenence. Just don't want to ignore things that may kill my block. I want to join the 300k club.

The above post gives me hope. For piece of mind I'm picking up stuff to do a compression test tomorrow. If all passes I'll do the valve covers, then timing belt depending on days off.

I looked for the milky oil and don't see any. I'm also not losing coolant that I can tell. It's just weird to notice the white clouds now, I've been driving this truck for the past 5 years in my current area and never noticed the white clouds out the exhaust on cold start ups..

Get a borescope for your smart phone and pull the plugs and look in the cylinders after it sits overnight. They are cheep.

Subaru owners replace headgaskets as preventive maintenance.


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[plcfcng]

One of the things I remember reading a while back that makes sense is that starting up first thing in the morning with a head gasket leak you will notice a miss that clears up after it warms up. As the leak gets worse the miss becomes more noticeable as time goes on. So your at a cross roads there are many who have HG failure at or before your mileage caused most likely from lack of maintenance of a cooling system.

A valve cover job could be done in a day a timing belt water pump job could be another day both as long as you don't run into any other problem. From the work that I did on the 4 HG that I have done if all went well with all the tools including special tools for Crankshaft and Camshaft bolts and a Torque wrench for the Crankshaft pulley nut. As well as sending heads to the Machine shop you would be looking at about 5 solid days of down time longer if you ran into problems maybe a day less if all went perfect and you stayed late.:jump:

 

[gamefreakgc]

I've only had one vehicle do what you're describing with Coolant sitting in the cylinder and smoking on start up. It is very distinct. You'll notice a lot more symptoms than just a puff of smoke. First off it'll be slow to crank as it tries to compress the Coolant in the cylinder, second it will mix in with the oil giving it a white milky consistency, and third it will puff massive white clouds of smoke for more than a minute while running terribly until its able to burn off all the Coolant and water.

The small puff of white smoke that burns off quickly and seemingly doesn't affect the engine at all is perfectly normal especially when it's colder out and nothing to worry about as far as I'm concerned.

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Exactly. You'll see it posted on here often, one of the first thing new owner of 4Runners comment on is all the steam that comes out on cold startups. These engines will blow a lot of water out on startup but don't fret, it's just the catalytic converters doing their job. The early morning steam show is normal.

I bought a 2000 4Runner with a blown head gasket last year for parts. Now THAT was a smoke show. Upon startup the engine stumbled so bad it would stall. I had to give it gas to keep it from dying and shook terribly while bellowing out CLOUDS of smoke. Not steam that whisps away and dissappears, a large plume of smoke that hangs in the air and will not go away and smells foul.

I'm positive you don't have a blown head gasket, you'd know it if you did. Or you will know it in a week after driving on a blown head gasket!

That was also the first time I encountered a 5VZ-FE that also shattered a piston. 300K miles on it, the kid actually took care of it too. I think the previous owner neglected the engine though, there were signs.

 

[G_Raw]

Pressure test:

Cylinder 1: 188
Cylinder 2: 192
Cylinder 3: 179
Cylinder 4: 184
Cylinder 5: 175
Cylinder 6: 188

Seems the front of the block is still holding pressure. With the passenger rear side being the lowest . Still pretty much in spec with FSM pressures though. But I'll watch for more symptoms and keep an eye on cylinder 3 and 5 since they are side by side and share the lowest pressures.

I thinks this COVID 19 cabin fever has me looking for things that aren't there.

Onward to valve covers and then timing belt.


Thanks all.

 

[shadow247]

I did smell the exhaust yesterday but smelt fine, like I said I couldn't replicate it at the time. I then realized since im thinking coolant is sitting in a chamber and gets burned off I'd need to make the engine burn it...So started up today normal steam, normal exhaust odor. Revved hard a few times and steam starts to change to noticeable white clouds blowing while holding revs. No white clouds when i stopped revving . Revved hard and high and went out to take a whiff and it smelt dare i say like a sweet spice? Cinnamon...ish?

I know doing my valve covers are no where near the heads, but I was going to do water pump and timing belt. And at that point I am close to my heads, and would need to redo all those upper gaskets anyways.

It's one of those do I spend 500 to do VC and timing vs 1200 to do VC, timing, and heads. Or worse do first option only to do second option a few months down the road...

Here's my take on it. I'm at 385k and thinking the same as you. But in the end, if you are not actually using coolant, then you don't have a gasket problem. I have the same random puff of white smoke in the morning sometimes, but my truck does not use noticeable amount of coolant in the past 5 years since I replaced the water pump/tb. I have added about a quart of coolant in that time. I say just fix what you know is broken.

Save money for down the line, or do a block test if you are really worried about it. These engines run forever if you take care of them. I think most HG's go as a result of the radiator or WP leaking and running low on coolant and overheating. I was super worried about mine as I overheated it 1 time at about 355k, but the past 30k has been flawless.

 

[phattyduck]

I think most HG's go as a result of the radiator or WP leaking and running low on coolant and overheating. I was super worried about mine as I overheated it 1 time at about 355k, but the past 30k has been flawless.

My pet theory is that lack of cooling system maintenance is the problem - wrong coolant and/or not changing the coolant. If that's the case, the head gasket corrodes from the coolant passage side instead of the cylinder side.

Same deal with the pink milkshake - I took my radiator apart at 270k miles / 18 years old and it was *perfect* inside (no corrosion around trans cooler) - but the coolant was changed regularly (even though it was just regular green) through the life of the truck.

-Charlie

 

[JohnMc]

There's no doubt that poor maintenance (allowing coolant to get old and change PH and start corroding things) can cause them to fail. As can overheating the engine. And poinging/detonation.

But aluminum heads on iron blocks do scrub against each other as they heat up and cool down. They simply expand and contract at different rates. And the head gasket is caught between them and serves as the buffer. Ye olde style composite gaskets worked great for iron heads on iron blocks - the mating surfaces were machined a little on the rough side, and this clamped onto and locked into the head gasket composite material and it all stayed in place for a long time. And when they started sticking aluminum heads on iron blocks, initially, they used the same techniques. Which works fine for a certain number of heating/cooling temperature cycles. But eventually, you're going to scrub that HG into failure. Even if everything else is in great shape.

Eventually, they started using a different style of gasket - MLS. Multi-Layer Steel. And they make the mating surfaces of the head and block smoother. Now the head and block cerep and squirm against each other - but they're less abrasive. And the gasket isn't depending on a rough surface to lock in and maintain strength - it's a much stouter stack of steel sheets.

Toyota went through at least 4 revisions of HG's on the 5VZ, following a recall on the first revision when a lot of them had failures. Revisions 2 and 3 are still composite, but with larger metal surfaces on one side of the gasket. Revision 4 is the MLS version.

And really - you have to give credit to the rest of the engine here. Many other cars probably would have had similar issues - if they had alu heads on iron blocks, but they tend to hit junkyards earlier. The 3.4 just keeps on going until more subtle design issues like this pop up.