The Peeing L20B! Headgasket questions..

[Buzzbomb]

Hey all,

 

1980 L20B, 175,000 miles..

 

Here's the story...I was driving yesterday to get some gas, all was fine, temp gauge was OK, everything was running great. I pulled into the station, I could see leaking coolant. Checker was a few miles up the road, so I hopped back in and headed up there thinking I blew a hose or something. I popped my hood when I pulled in Checker's lot, and what do I see but a stream of coolant shooting out of the back of the engine by the heater hose boss and onto the inner fender! It's like my truck got pissed and started taking a whizz!

 

I was pretty bummed, but I DID carry some extra coolant and a small bottle of Bar's Leaks with me, and that was enough to get me home. I know that some don't believe in Bar's Leaks, but I do because of having this problem before, and putting literally 20,000 miles on the truck after having done this the first time. That being said, this leak is not a pinhole squirt, and I tried another can of Bar's Leaks to no avail.

 

My oil is fine, there is no milkshake looking color on the dipstick or filler cap. It appears to be an external only headgasket leak. I have no smoke out of the tailpipe, it runs and idles fine.

 

I really like this truck..I've had it a LONG time. I popped open the Haynes manual, and man! It sounds like you have to practically dissassemble the engine to take the head gasket off! Is that true? Or is that just the way you are "supposed" to do it, but like anything else, a group of enthusiasts with experience know a better way? I know you have to make sure you don't drop the timing chain, but cutting a board for that is obviously not a problem. It's the other stuff that sounds pretty involved.

 

How involved is replacing a headgasket on an L20B? How long of a job is it usually? Do you really have to tear all the manifolds off the head, or is it too heavy to be lifted off? I'm sure I could handle the job, as I've done the usual brake stuff, replaced the water pump, dropped the driveshaft, etc. I've rebuilt Holley's and Qjets with no problem, but honestly have never tried anything of this magnitude.

 

How tough is it to replace the headgasket on the L20B? Sorry for the length of the thread.

Edited January 22, 2009 by Buzzbomb

[BACARDI_DWB]

you have one of the easiest engines to replace a head gasket on!! BAR NONE!

 

empty oil and coolant

unbolt intake and exhaust

undo the plug wires

take off the valve cover

here is the tricky part. take a big handled screwdriver and lock it (the handle of the screwdriver) inbetween the chain tensioner so the chain will not slack off when you undo the cam gear. (if you do drop the chain then the install got alot harder)

undo the cam gear but mark it before you do.

unbolt the head and pull it off

clean up the head and block surface

 

reassemble.

 

i may have missed a step but the awesome guys here will catch it.

 

i have done mine in under 30 min

Edited January 22, 2009 by BACARDI_DWB

[ppeters914]

Process covered in the L-Motor God's video, right?

[banzai510(hainz)]

Jeff Spicoli's Dad was a TV repair man and he could fix anything(from "Fast Times at Ridgemont High"

 

read the manual and watch this

http://www.guba.com/general/search?query=hainz&set=5&x=43&y=6

 

have a big adj wrench and put on the cam boss lobes. The 2 in the center(since its a L20 it will have them). turn motor Counterclock wise till wrench rest on head bolt)

 

break the cam bolt and the crank bolt at bottom then(remove the wrench) set motor to TDC(top Dead Center) On or near Zero deg on the cam and crank sproket and try not to move them after this.

 

rest is in the vid. If Blly Idol can do it,So can you.

 

take your time!!!!!!!!!

[banzai510(hainz)]

Well its EZER if a early L16 in 521/510 as I can get my hand in thereand losen the intake /exhaust bolts.

 

as the later L20s are full of emission shit in the way and the lower intake exhaust bolts are a bitch to get at.

 

Sockets ,extensions and U joints!!!!!!!!

 

I have remove a L20 intake off but motor was out of the car and it was still a pain. HARDER in the car

[datzenmike]

Change head gasket on an L engine:

 

Drain coolant at least half way.

 

Separate exhaust to down pipe.

 

Set engine at TDC... important! GET IT RIGHT! Put transmission in neutral and block wheels also IMPORTANT, remove air filter, unhook throttle cable, any air pump hoses at air pump. (if equipped) vacuum line to brake booster, PCV hose at intake, idle cut and choke heater wires, vacuum line to distributor, top rad hose at head, vacuum line to charcoal canister, unplug spark plug wires at plugs and move out of way, unhook temperature gauge wire at thermostat housing, disconnect fuel line at pump inlet, remove battery ground cable, remove top heater hose from back of head, unhook water return hose from intake manifold where it joins the lower rad hose, remove valve cover, slip socket extension through cam sprocket to lock it and loosen cam sprocket nut... don't remove yet!, check you're still at TDC (and adjust) and drive wooden VEE wedge down between timing chain and chain guides to lock it in place. This will prevent the chain tensioner from falling out... if you don't know, find out or you will be doing twice the work to fix this mistake, mark the timing chain and cam sprocket so you can assemble in same relationship, remove cam sprocket, loosen and remove 10mm Allen head bolts starting with the front two, then the back two and alternating front and back and working toward the middle, keep track of where they go for reassembly, remove the two 10mm head bolts at front of head that screw into the timing cover.

 

This should have the majority of things disconnected so that you can remove the head AND the intake and exhaust manifolds as a unit. Grasp the fuel pump and intake and rock from side to side and the head should easily break loose. Get help and lift the head with manifolds up and off. Avoid turning the carb upside down if possible to prevent stirring up sediment. If worried about this you can remove the carb before hand. Find the two alignment rings or dowels either in the head or block, clean and re-install when ready to assemble. Locate the blown area of the gasket and inspect it.

 

Tilt head just enough to wire brush or use an angle grinder with wire wheel. Use care, the aluminum is soft. Get it as smooth and clean as possible. If this had blown between cylinders or you had driven it high into the hot range with lots of steam I would say check the head for warps. Thoroughly clean the head bolt threads and wipe with an oily rag. Inspect the blown gasket area, there should be no indication of it on the clean surface.

 

Fill the middle two cylinders with rags to collect the dirt and wire wheel the block surface. Again, as clean as you possibly can. You can't over clean these two surfaces. Clean out head bolt holes thoroughly IMPORTANT! Inspect the blown gasket area, there should be no indication of it on the clean surface.

 

Install new gasket on block dowels. Lift head onto block and finger tighten the two rows of head bolts. Make sure that the cam has not been rotated while the head was off. The aligning dowel pin at the front should be at 12 o'clock and the first two lobes set at 10 and 2 o'clock.

 

Use a torque wrench and begin tightening in the middle and working outwards to front and back like below:

 

RAD

7...8 P

3...4 L

1...2 U

5...6 G

9..10 S

 

Use this sequence and tighten to 20 ft lbs. Start at the beginning and in the same sequence torque to 40 ft lbs. Finally in the same sequence torque to a final 60 ft lbs. A few lbs either way is not as important as the sequence that is used.

 

Match cam sprocket mark to timing chain mark and install onto cam alignment dowel, don't forget fuel pump eccentric. Tighten and remove wooden wedge. The rest is more or less the reverse of disassembly. After a dozen full warm ups and cool downs, check the head bolt torque with engine cold. You might want to warm engine and set the valve lash while the valve cover is off too.

 

I had the gasket blow on my '78 L20B for no reason I could see other than 300,000 km. It blew out water above the #3 spark plug but was also blowing steam out the exhaust. $23 for the gasket and $2 for gear clamps I didn't use. A very good, very cheap and easy fix.

Edited January 23, 2009 by datzenmike

[mklotz70]

I haven't tried this personally, but I heard about it from a guy getting parts in front of me.....so I did some research.....

 

Look up Sodium Silicate .....pretty wild stuff and you can't get it at Walgreens(so he said) .....anyway....wiki says it will plug a head gasket leak permenantly....worth a try?? I'd love to see you try it since the worse case is that you'll still have to swap the gasket.

[lynchfourtwenty]

I haven't tried this personally, but I heard about it from a guy getting parts in front of me.....so I did some research.....

 

Look up Sodium Silicate .....pretty wild stuff and you can't get it at Walgreens(so he said) .....anyway....wiki says it will plug a head gasket leak permenantly....worth a try?? I'd love to see you try it since the worse case is that you'll still have to swap the gasket.

 

sounds like something a tweeker would use...

 

me an my buddy sold a 87 nissan sentra once, basicly the oil was milkshake an all that... we sold it to this tweeker and he used "some stuff" on it an changed the oil an continued drivin the car for a few months..

[Buzzbomb]

Thanks for all the responses! I really appreciate it..THe detailed responses sure are helpful!

 

This is one of those things that anybody else other than on this board would probably call it quits since the truck is so old and isn't in A1 body condition. It's still a nice truck for it's age really, and runs great even with the coolant spewing out from the side of the engine :eek: ...Seriously, I've gotten MANY years of excellent service from this truck and am not at all eager to throw in the towel with it. I've also taken good mechanical care of it for those years, so I know how it's been treated.

 

Hainz, yes it is an L20B, and yes it does have all that emissions junk in the way. That is the thing that appears to make it more difficult than it really seems like it needs to be. I took a look at your video, which is awesome :yes: , and that L16? you are working on looks super easy. Like you said, it looks like those bolts on that version of the engine are so accesible you can literally set them with your fingers!

 

DatzenMike, I actually read your post about your truck when I did a search and saw that you did this without taking off all the manifolds which is what made me wonder if I could do the same on my engine. Thanks for the super detailed write up! With your write up, the great video, and the Haynes manual thrown in for good measure, it makes more sense than ever to at least attempt to fix this myself.

 

I'm going take a long hard look at all the stuff on the engine and see what I'm up against. Luckily, I have a Federal model without an airpump, if that's any consolation. One thing I do wonder about is that my radiator isn't getting warm, but I guess that is because the coolant isn't circulating properly since it's shooting out the back of the block/head.

 

As for the sodium silicate, isn't that like liquid glass or something? I think I saw that somewhere too after doing a Google search, and saw that it can work. I BELIEVE you have to drain the coolant and use water when you use that, which is OK at this point because the coolant doesn't trickle, it shoots out, so no loss there :P . I will say one thing about similar fixes; Bar's Leaks DOES work for smaller leaks. It band-aided this one time before when it was more of a trickle/small leak 20,000 miles ago, and it did slow the leak enough to get me home.

[mklotz70]

yep...liquid glass.

 

I've used Bars before and it plugged up the radiator on me. Prestone super sealer is much better in my experience.

 

http://en.wikipedia.org/wiki/Sodium_silicate

 

http://www.ehow.com/how_2002031_use-block-sealer.html

[MikeRL411]

Sodium Silicate is known as "Water Glass" and used to be used to preserve eggs before good refrigeration was available. Farm supply shops may still carry it. It used to be in the kiddie chemistry sets sold before "the authorities" found out that they contained all the ingredients [and sometimes instructions] for making black powder.

[banzai510(hainz)]

Buzzbomb

 

ask yourself maybe better to remove the exhaust and pull the whole motor.

 

175Kmiles maybe better to get it rebuilt or at least a new chian kit. Clutch kit ect?????????????

[hang_510]

It sounds like you have to practically dissassemble the engine to take the head gasket off! Is that true? Or is that just the way you are "supposed" to do it,

 

the top end is practically the entire engine :lol:

 

since you HAVE to remove the EX to remove the head, plan on pulling the IN too and replacing that gasket.

 

it is really simple and w/ basic knowledge (and parts in hand) a few hours youll be back on the road :thumbup:

 

 

is there a bad heater hose that could make this repair simple???

 

 

i dont like the leak stop products, all(3 brands) have made the situation worse and clogged the rad, which further exacerbated the problem.

[lynchfourtwenty]

Buzzbomb

 

ask yourself maybe better to remove the exhaust and pull the whole motor.

 

175Kmiles maybe better to get it rebuilt or at least a new chian kit. Clutch kit ect?????????????

 

lol i was gonna say that too.

[RacnJsn95]

Why not just unhook the exhaust pipe from the exhaust manifold, and pull the head with the intake and exhaust still bolted on? It's a little heavier, but saves time. I've done it a few times.

[Buzzbomb]

I really appreciate all the responses..It gives me some direction in trying the easiest stuff first and the hard stuff last, even if the hard stuff is invevitable at some point :)

 

I had basically a full bottle of Bar's gray bottle left over from another vehicle. So, I figure what the heck, why not try it. I flushed the old stuff out of the system with what must have been 50 gallons of water; it was clear at all drain points, even the one that shouldn't be there :P . I ran the truck on straight water until it was operating temp to loosen up more of what might have been left, and also to get the thermostat open so the hole would get hit with the stop leak. I drained the water, filled it with 50/50, and the Bar's worked again...for about 5 minutes. The leak totally stopped, however, this was with the rad cap off. I put the cap on, it started leaking. Since you can't drive with no cap, it isn't fixed. I didn't expect it to be since the leak is pretty good size, but it does leak less while sitting than it did the other day, FWIW.

 

As for the sodium silicate, I might try it. It turns out that the Bar's HeadGasket treatment is Sodium Silicate based, so I know where to get the stuff. It's worth it for me to try it because I live where we actually have winter, so it would be great if I could bandaid it until the weather gets better. I could think of worse ways to blow $10, and if it somehow worked, the $10 was worth it in buying some time. It's not a heater hose blowing coolant at the block, but I sure wish it was!

 

The clutch only has 35,000 miles on it, and the engine runs fine. It doesn't smoke white or blue, and will start when it's 0 degrees out with little fuss. I ran a compression test on it over the Summer when I had trouble starting it due to what turned out to be the battery just not having quite enough juice, and I had 145 or so pounds of compression in all cylinders except one that had 140. Keep in mind this test was done with the engine cold and that I'm at over 6000 ft. in altitude.

 

The limiting factor with pulling the whole shebang out for me is space and equipment. I don't have a cherry picker, and don't know how heavy the head/intake/exhaust is all together. Would two people be able to lift it all out with the hood off?

Edited January 24, 2009 by Buzzbomb

[datzenmike]

.......This should have the majority of things disconnected so that you can remove the head AND the intake and exhaust manifolds as a unit.....

 

Been sayin; that all along. I hate undoing the manifolds ON the vehicle. Better to take head off first or best just leave it alone.:mellow:

 

Read the label on the pour in stuff. Says to get to a shop for proper repairs ASAP

 

I've heard of a couple of tins of condensed milk to seal up leaks and even a fresh egg in the rad.:eek:

Edited January 25, 2009 by datzenmike

[lynchfourtwenty]

I've heard of a couple of tins of condensed milk to seal up leaks and even a fresh egg in the rad.:eek:

 

lol... OK MACGUYVER.. :fu:

[Buzzbomb]

Update on this..

 

I decided that using the quick fix stuff again was a waste of time. I figured the time and money spent flushing out and draining could be spent actually taking stuff off to fix the headgasket. There's the chance, as others suggested, that this time I wouldn't be so lucky with the stop leak, and that it would plug other things up and cost me more than a headgasket gasket kit would have cost. I've been taking things off and will do this as time (and weather) allows since I luckily have other means of transportation. I've heard of the egg, milk, and pepper tricks but didn't need a Grand SLam breakfast coming out the tailpipe :lol:

 

One of the determining factors for this was watching Hainz's awesome video. I put the engine on TDC, and wanted to see where the timing chain marks were to see if this job would need more to be right than I originally expected. It turns out that my V notch and - mark are dead nuts on. It isn't a little to the right or left, it is square over that V notch. Seeing that was really the tipping point for my decision.

 

Since I'm not in a total rush to do this, I am at least attempting to take the manifolds off in the truck. First, I have back trouble, and figure it would be lighter coming out separately, and second, I'm getting the headgasket kit and figured I would just go ahead and replace the gaskets. If I can get it off that way, fine. I am down to the two underside bolts of the intake, and can actually get my fingers on them. If I can get those off, it comes off. If I can't get them, which I THINK I can with the right tools, I'll just pull it off as a unit and hope it isn't that heavy. I DO see that taking them off all together would work great, it's just a few other factors that I have to consider.

 

I also found a tool that is made specifically for the timing chain on L series Datsuns, and the nice thing was that it was on clearance at Checker for less than 5 bucks! That's cheaper than buying wood and taking the time to cut a tool out of the wood..

 

Turns out I needed to take the EGR passageway off regardless of this headgasket job. It was totally plugged with carbon, so no loss there taking that apart. Luckily, tHe gasket is in the kit.

 

LOTS and LOTS of PBlaster, patience, great instructions, Hainz's video, and hopefully this will continue to go smooth, but I may have to ask another question or 20 :) ...Who knows..

[Buzzbomb]

Quick update here....

 

I've torn it all apart..I soaked the shiznit out of the exhaust bolts, and took it all off without breaking a single bolt, which was a shock because that stuff has been on there forever. I actually had the right tools to at least try to take the intake off (12mm u-joint), and it came off in 10 minutes.

 

I'm in the process of razor blading the old gaskets off, and will be taking the head off when I get my Ishino gasket kit..Thanks so far to all the awesome instructions here and Hainz's video...It's really helped, and as long as my chain stuffer works OK and I use Datzenmike's torque instructions, I suppose it's all gravy from there :D ..At least that's what I hope :o

[hang_510]

:thumbup: