Cyl's 1, 3 + 4 @ 150 psi -#2 @ 130

[skibum]

Hello,

I went down to Houston last winter and bought our '88 4WD manual (third in a, most likely, long line of Toyota vans). It runs good, starts good, but does have a bit of a high idle, comparatively to our '87's, but it goes through antifreeze.

I flew to TX and drove the van up to MN and flew back to CA to get this van, and the reasonable price ($2500) had me commited, so I bought it "as-is". It's from Texas, so there is no rust, so I was willing to take on anything mechanical.

Anyway, on the trip to MN, I had to stop about every 120 miles and add about a quart of antifreeze. It would cruise along with the temp guage at about 11:00, way better than my other 2 ever did. but then it would start creeping up and just keep going (I'm used to my other 2 getting hot, then I drop a gear and get the pump going to keep the heat down). I started verifying the rising temp by feeling the heater vents and they were getting cold, so I knew I was losing coolant. The further down the road I got, the more comfortable I was with the van, so the speed increased, whereby the distance between coolant loss shortened to 40 - 60 miles.

My wife flew back to MN this spring (she had some visiting to do) and I drove me, the dogs and cats back to MN, but I had left the van at her brother's (250 miles south of us), so she volunteered to drive it up north. I was hesitant to stick her with having to keep stopping and topping off the radiator, but she insisted. We met in Duluth, she having driven 150 miles and she hadn't had to stop. She drives slower than me.
Regardless, I know that there is a problem, but we can drive around @ 55 mph and do a lot of running around, as long as we don't really get the motor too overworked.

Anyway, I finally got around to doing a compression test today and got the results I spoke of in my title. #'s 1, 3 + 4 came up to 150 lbs. quickly ( maybe 3 cranks), while # 2 only came up to 130 lbs., but about 5 or 6 cranks.

I'm thinking that since I didn't hit a < 10% variation that I've got a head gasket at issue. I figure one of you will confirm this, but I'm open to other ideas that may be less of a chore. I don't see any evidence of coolant leaking, so I'm kind of ruling that out.

When it gets hot it bubbles out through the overflow res, so I replaced the cap. It doesn't seem to tap the reservoir, very often, only about 3 times has the radi light come on. Usually, it's plumb full.

The oil is oily, no chocolate milk.

Thanks for any comments you have,
Scott

[JRSJ]

Sounds like you have a tiny leak somewhere in your head gasket. I had the same problem with mine -- only after driving long distances would the combustion gases finally push out enough coolant to start an overheating episode.


When I pulled the head and inspected the old gasket, the fire-ring on cylinder 4 was warped, and compression gases were pushing into the nearest coolant jacket. Erosion near the jacket was evident, caused by prolonged exposure to the warped fire ring. Long story short, the head was decked and valves resealed. (The valves and engine block were in great condition.) Its fine and dandy to replace a head gasket, but finding out what caused it to overheat and eventually blow in the first place is the key. I ended up re-coring my rad, replacing my cap, waterpump and thermostat with the gasket.

What kind of condition is the rad and fan clutch in? Has the waterpump ever been replaced? How did the coolant look when you first saw the van? Combustion gases may taint your coolant over time, and could have indicated the condition of your cooling system. (Of course if the previous owner was constantly topping up coolant then it might be hard to judge.)


Doing a head gasket isn't as bad as it sounds. If you're mechanically inclined -- the Engine Mechanical section of the service manual outlines it pretty well. Removing the drivers seat hatch helps, and using stripped telephone wire (underneath the insulation is an assortment of coloured wires that I used for labeling vacuum lines and any electrical wires / coolant hoses.) can take some of the guess work out of slapping the motor back together.



Since the van is a 5spd 4X4, and in great cosmetic condition -- it would be a damn shame not to do a replacement.


JRSJ

[skibum]

JRSJ,

I suspected that was the case, and now I've gotten the confirmation. Off with your head!

I am mechanically inclined, so I will be doing the repair. Fortunately, our 1st TV is now a donor, so I will keep this one alive.

On hindsight, the coolant was a bit murky, so that could have been an indicator that something was up. I'd have still made the purchase, but might have tried to haggle a bit more (He was asking $3K). He had just had a salvage motor put in, with a guarantee, but that doesn't do me a lot of good 1800 miles away. I am still very happy with the 5 sp, though, and my wife really gets a kick out of creeping up our hill in low range .

I was really pleased with the way the doors and door handles work (back and side). I have to reach inside from the passenger door to open my other one(s) and the back latch is on it's last leg, so that's worth it by itself.

Also, the shop that put the motor in had sense enough to install a new radiator. I'm not sure if it's the right one, but it is doing a fine job when it's got coolant. The reason that I'm not sure if it's right is that the shroud has no holes for a screw to go through, but the radiator has nuts welded on to receive the screws that would go through the shroud. Nothing a 1/4" drill bit and a couple tie wraps didn't fix, though.

Thanks for the reply. I guess I know what I'll be doing in my spare time.

Scott

[theschnell]

Help me understand in case I find myself in a similar situation. So no apparent leaks, and your oil is ok. So if it's a head gasket, doesn't that mean that the only other option is out the exhaust? I had a van that used coolant, and every time I would start it, it would cough out a bunch of white smoke for about 5-10 seconds, but then it would run fine. We put some of that stop leak stuff in. I know you guys hate that stuff, but I had bought the van for $150, so I didn't have much to lose. Anyway, it would use about a cup a day of coolant if I drove a lot, like 200 miles +, but it was always good and cool, once we fixed some other problems. I think eventually we put a second round of stop leak, after we had gotten it pretty hot and then replace the coolant, and it quit leaking altogether. My point is NOT that you used use that stop leak stuff, but rather that it seems to me that if a head gasket is your problem, you should know by the color of your exhaust, the condition of your oil, or an exterior leak. Is there something else I'm missing? Hate to see you do a head gasket if its something else.

[JRSJ]

Help me understand in case I find myself in a similar situation. So no apparent leaks, and your oil is ok. So if it's a head gasket, doesn't that mean that the only other option is out the exhaust? I had a van that used coolant, and every time I would start it, it would cough out a bunch of white smoke for about 5-10 seconds, but then it would run fine. We put some of that stop leak stuff in. I know you guys hate that stuff, but I had bought the van for $150, so I didn't have much to lose. Anyway, it would use about a cup a day of coolant if I drove a lot, like 200 miles +, but it was always good and cool, once we fixed some other problems. I think eventually we put a second round of stop leak, after we had gotten it pretty hot and then replace the coolant, and it quit leaking altogether. My point is NOT that you used use that stop leak stuff, but rather that it seems to me that if a head gasket is your problem, you should know by the color of your exhaust, the condition of your oil, or an exterior leak. Is there something else I'm missing? Hate to see you do a head gasket if its something else.

There are a few general symptoms of a blown head gasket, or gasket that is starting to fail. Depending where on the gasket the failure is and how severe (block/head cracked/erosion etc) usually dictates the symptoms you receive. Sometimes it can be one symptom, or multiple -- blown head gaskets do not discriminate.

In talking with other TV owners, the single most common sign of a head gasket failure was overflowing of the coolant tank. There is only one reason why an overflow tank would bubble out violently, and that is a significant decrease in pressure via combustion gases pushing coolant out. When enough pressure is lost, the boiling point of coolant will become critically lower. This decrease in pressure will cause coolant to steam/and gush out of the tank.

[theschnell]

That makes sense. Thanks.

[skibum]

Well, I took the head off today, finally. This is my busy season, with my work, but I found myself with a day, so I dove in. Thanks for the link to the manual, although the guy I bought the van from had given me that same manual. I was able to print a couple of the pertinent pages (head bolt removal sequence) from your link, though, so that was a plus.

The inside of the valve cover was pretty gunked up (first picture below), but I blew that out (after removal). I will inspect the valves, etc. on my next day off, to see if I need to get them ground.






I didn't see any direct conduit from the water jacket openings to the cylinder, so I'm a little puzzled as to where my coolant may have been going. I'm kind of keying on #2 cylinder, due to the compression test and did see a less than perfect area around one of the water ports next to #2 (first picture below). It's kind of "dished out" around the port. The head gasket is sort of eroded around that port, too.




I don't know if there is a size limit to attached pictures, but I uploaded 1 MB photos, but they came out this size (100 kb).

The block and the head are flat. There was a lot of buildup in the water jacket ports (rusty looking).

The coolant in the overflow tank is a bit murky, so I still suspect the head gasket.

I'll be proceeding with my project, but if anyone has any ideas along the way, I'm open to your thoughts.

Thanks again,
Scott

[JRSJ]

Sorry for the late reply Skibum, glad to see you're getting elbows deep in a HG replacement!

Definitely looks like your HG was in the beginning stages of blowing -- good to see that its being taken care of now. Post a video of your Van running when its made a full recovery!


Its kind of embarrassing, but this advice could better serve the community. Remember to replace all the crush gaskets for your fuel line as they are not reusable. I accidentally screwed the Fuel Pulsation Dampener on top of my fuel filter (instead of on the fuel rail) and had a gas leak because those gaskets are not reusable. In hindsight, it was probably better that it was leaking on the passenger side instead of over the exhaust manifold.


Oh, and replacing all worn and crusty hoses would add peace of mind as well. ;D

[skibum]

Hi JSRJ and all,

Thanks for the response.

The "crush" gaskets you referred to, I'm thinking, are the copper gaskets that go on both sides of the banjo fittings? I've never replaced those on anything I've worked on over the years, but I am willing to heed good advice.

The head gasket looked like it might have been leaking between a large hole at the front of the engine and Cyl. #1. There was some "shellac" on the steel ring in that area and the exhaust valve for #1 was quite a bit darker than 2, 3 and 4.

I took the head in for valve grinding and surfacing. I took it to Midwest Engine in Duluth MN (shameless plug, because he's done me right in the past).

I do plan on replacing the various rubber hoses during the reassembly process. The "hose of death" plate seems to look OK, but should I consider having one made and replacing it, as well? I saw a thread on that either here or TVP.

I'll update as the process moves forward.

Thanks again,
Scott

[JRSJ]

The "crush" gaskets you referred to, I'm thinking, are the copper gaskets that go on both sides of the banjo fittings? I've never replaced those on anything I've worked on over the years, but I am willing to heed good advice.

I too am guilty of reusing the simple copper gaskets, if I don't have any new ones on hand. I argue that for the price, its easy to justify replacing them all. However, the gasket I'm referring to that will need replacing is the one used on the Fuel Pulsation Damper (FPD). Part# 23232-41081. Its larger than the copper banjo gaskets, and has four tabs used to center on the FPD.



In Canada the list price for them at the dealership was $3.40 per gasket . I ended up buying four just incase. (They told me there were only 93 left in their whole inventory.)

Happy Wrenching!

[NEC]

look very closely at the head gasket (both sides). -particularly all around the steel sealing ring surface for the %2 cyl. If you see any cracks in the ring or any areas of noticeable discoloration at the sealing surface this is where your leak was coming from. The common failure point is between the cyl wall and water jacket. If you have even a slightly blown hg it is easy to identify by a trained eye. If you were having large amounts of coolant in the combustion chamber you will also notice the affected piston to have a lot less carbon on it and will look very clean. You can test your valves for leakdown by setting the head upside down and filling the combustion chambers with oil/atf/brake fluid or whatever you got and letting it sit overnight. in the am if you have lower fluid levels in one or more combustion chambers you know you have a selaing problem. This test will not tell you the overall condition of your valve guides, but is a good indicator of whether you have a major problem with the valves.

[NEC]

sorry I didn't read that you already inspected the hg and went to mochine shop...

[NEC]

Just another thought: if you still have the head off inspect all the cylinder bores very well. you will likely notice a wear pattern in the bore just below the top of the piston stroke where the rings ride. this is normal to an extent. What you want to see it that the wear pattern is uniform all the way around the cylinder wall and continues all the way to the top of the #1 piston ring's travel. If you see any vertical lines or unevenly worn/less shiny areas in the cylinder walls note the position of where they start/end in regard to the overall depth of the normal wear pattern in the cylinder wall. If the vertical lines are just below the top of the normal wear pattern it almost always means you have a broken/stuck #2 compression ring and that piston needs to come out to have a better look. If the vertical lines come all the way to the top they can mean the same about the top ring. This is not common unless the engine was overheated badly or really neglected. Just another thing that can be easily noticed by a trained eye/overlooked by anyone else.

[skibum]

Thanks for bringing up the cylinderrs, themselves. I've been keying on the head gasket as the problem, but it didn't show any signs of leaking into #2. The #1 cylinder seems to be where the leaking antifreeze must have been going, as the exhaust valve on that cylinder was a different color than the others. There was a little "shellac-ing" on the steel ring part of the head gasket, near a large antifreeze port on the front of the motor.

I'm hoping that the weak compression in #2 was due to the valves, but I will inspect the cylinder bore(s) just for peace of mind. I casually looked at them when I was pulling the head and didn't see anything glaringly wrong. I'll look closer at the ring conditions that you mentioned.

I'll update as the project moves forward.

Thanks again,
Scott