strange engine behaviour on 2L-TE (1 Viewer)

[light_duty]

Hey all, any ideas apprciated:

Here's the lowdown: I picked up the LJ78 this morning in Calgary. Everything ran great: engine temp never left the lower part of the dial, EGTs never topped 850F. Ran a steady 100kph at about 2800 rpm for over 2 hours, no problems...

...until I hit Lethbridge. As soon as I hit stop lights and started idling here and there, the temp needle started rising to the middle of the dial. I stopped by my buddy's house, and I let it idle for a minute or two. When I came back to the car, the gauge was in the top 2/3 and a small puddle of coolant was forming under the truck. I checked the fan, and it was spinning away. Anyway, to avoid another tow, I drove the sucker straight home, and by the time I got home, the temp gauge was at 3/4 and the coolant in the expansion tank was bubbling away - very much like what happened on Monday when it boiled over. I turned the truck off and the tank continued to bubble for a few minutes, and some coolant pooled on the ground beneath.

I guess that this probably means cracked head or failed gasket, since it does sound like there is a lot of gas escaping through the expansion tank, but why would it run beautifully for two full hours before acting up in around-town driving? I've got a new rad cap and new thermostat. What about a blockage in the cooling system somewhere? Water pump problem? Would something like that cause these symptoms? Anyone have any ideas?

Cheers,
Robin

 

[expat]

Sorry, I can't help. But damn that sucks. As a previous owner of an 88 vanagon, I can appreciate the desire for at least one reliable vehicle.

 

[roscoFJ73]

Hi Robin. These things will really test you.
I tend to think it is not a head gasket as it would have played up really bad at highway speed.

The bubbles could be big bubbles of steam that build up around the cyl bores and force their way to the top.
This could be a blockage or circulation problem
Have you checked the top of the oil filler cap for a cappucino froth which often acompanies a cyl head leak?
Someone posted some info on a coolant analyser recently that tells you if there are hydrocarbons present in the coolant solution .
Lets stick with the cheap and easy stuff 1st but refrain from driving it.

 

[light_duty]

Rosco: Thanks for your reply. What you say makes sense. I did check for froth on the oil cap when we changed the oil, and saw none. I'll check again tomorrow, now that I've driven it a bit.

I'll have to look into that HC in the coolant test. The pressure test I performed with Wayne showed no pressure loss at operating temp over several minutes - the needle held steady at 16 psi without moving a hair. I know some here distrust the pressure test, and I defer to their expertise, since I am still wet behind the ears when it comes to diesels.

To my mind, the truck isn't behaving like a it has a cracked head, but more like there is coolant that is getting too hot, either because it's not circulating fast enough, or it's getting trapped somewhere and boiling. This would be consistent with what Wayne and I found when we were installing the circulating heater: there wasn't too much waste coolant in the tray after we sliced open the lower rad hose. Maybe there's crud in the rad (or elsewhere) that's restricting coolant flow. At high speeds, the coolant cools enough, but around town, it doesn't...?

The truck starts well, produces no white smoke, idles nice, etc. It just gets a little hot under the collar sometimes. I'll do a search on flushing the cooling system.

thanks and cheers!
Robin

 

[Greg_B]

You can leave the pressure tester on and run it. See if it pulses, which may indicate a leaky head gasket. That and the test strip would assist in eliminating...

hth's and hope you get it sorted with something easy.

gb

 

[crushers]

my "guess" would be a air bubble was trapped and when you slowed down it caused the truck to run warmer by blocking the flow. once it reached the rad cap is blew past and into the over flow.

my suggestion is each morning before you fire it up top up the coolant. do this for about a week and see if the amount you add is less by the end of the week. trapped air can be a PITA to get rid of. when Toyota went from the rad cap to the "thermostate" cap it created a real pain for us all.

just my guess and suggetion

BTW, glad you made it home okay.

cheers

 

[light_duty]

Thanks for the suggestion, Wayne. I'll give it a try. Will idling do the trick? I don't have the thing registered yet, so I can't drive it, but if I fire it up and let it idle, will that move the bubbles through?

Anyway, if it was a bubble, it was a fairly large one(s), since I lost probably 2 litres of coolant in about 25 minutes through the expansion tank. That's why I'm still wondering if there's a blockage somewhere in the system, maybe causing local overheating of the cooling fluid...? I'm still not convinced it's a cracked head, but will try to locate one of those test kits here in town.

I did a search, but didn't find much on flushing the rad, block, etc. Can this be done with a regular hose and nozzle? Or do I need something more powerful?

Robin

P.S. Props to Wayne, who is one of the most straight-up people I've ever met. He spent the better part of Monday with me getting this truck roadworthy, even though I didn't buy it from him. And then he fed us some of the best buffalo chili ever. Should I ever decide to "upgrade" to a BJ74, I'll be buying it though Wayne! I'm sure I'm preaching to the choir on this forum, but it's still good to give credit where credit is due.

 

[roscoFJ73]

Robin,another thought is being a JDM vehicle its probably hasnt done much high speed work like your 2 hour drive at 100klm/h and it may have stirred up a pile of sediment which is now blocking the radiator.
As a reliminlary examination you can spray a fine mist of water onto the radiator while its hot.
If there are blocked cores they will remain cooler and the water wil linger ,while on the unblocked cores the sprayed water will evaporate quicker.
In theory because Ive never tried it

An airlock can be overcome by filling the coolant system from the highest point which is the heater hoses where they exit the firewall.
Its best done when warm so the thermostat is open.
Leave the cap off until it overflows then put the cap on and fill it some more.


Ive neve seen a thermostat on these but they are often a good place to look for restrictions or it maybe its only partially opening.
Any thermo should open withih 5-6 minutes and you can feel the temp of the bottom hose get hotter as soon as it opens.

 

[crushers]

you have a good point there, i have had a couple come through that had the upper rad hose disinigrating from the inside out. i always keep an eye out for black particles when i am changing out the rad coolant. there was no contaminates in the small remaining amount of fluid that i saw. i put a brand new factory thermostate in and i tested it before installing it.

BTW, i just got back from a LJ78 5 spd run to Edmonton and back. 6 hours at 120-140 with bursts up to 150. the pyro sat at about 800-1000F most of the way. one thing i did find is the engine works hard to get up to speed but once there it takes very little to keep the speed the same. you REALLY have to watch the long gentle hills as they can fool you. oh, and the fuel milage sucks big time at that speed. no over heating problems and no hick-ups at all.

thanks for the compliments, Robin. i appreciate it and it was a blast meeting you and .... (crap, i knew i would forget your friends name, sorry). anytime you are in town stop by.

try the coolant addition for a bit before getting to worked up.
i am sure it will be an easy fix.

cheers

 

[harveya]

Here is a simple test to see if the head has cracked - it is pretty much a confirmed if it fails this test as there is very little other things to cause combustion gases in the coolant - head gaskets don't tend to fail on the 2LTE - the head goes first.

Let the vehicle stand over night until it is cold.

Take off the radiator cap and start the engine. If the water bubbles out or gushes within a minute then you have combustion gases and the head needs to come off. It will either be a gasket (very very unlikely) or the head cracked between the valves.

However that being said, you are as likely to have a slightly blocked radiator or very likely an air bubble in the system. The 2LTE is notorious for being an absolute pain to get it filled with no air locks.

Have a look at this link

http://www.allhead.com.au/cooling.html

This is often the only way to clear out the airlocks on the system.

Also the viscous fan may be spinning but is it spinning enough - might need to rebuild the viscous coupling.

A good flush of the cooling system is a must with heater on full when you first get hold of a 2LTE. It isn't worth skipping this stage.

Also while you are at it, change the timing belt, oil and filters.

 

[Greg_B]

Have a look at this link

http://www.allhead.com.au/cooling.html

This is often the only way to clear out the airlocks on the system.

Great info and link.

Thanks!

gb

 

[light_duty]

Thanks everyone...now I've just got to wait for a chinook to blow this frigid arctic air back where it belongs so I can get to work!

A garage, a garage! My kingdom for a garage!

Robin

 

[light_duty]

In case anyone's interested, I'll share my experiences with the LJ78 tonight.

While my plan was to flush the rad and cooling system, I first decided to follow harveya's advice and start the truck with the rad cap off and look for bubbles and overflowing. Well, there were plenty of each, let me tell you, right from when it first fired up. But the bubbles weren't what I would have expected from an exhaust gas leak - they were big, gurgling bubbles pushing a fair bit of coolant out of the filler neck. Anyway, I started it, let it run for a bit, refilled, started, filled, started, filled, etc. for about 8-10 cycles. Toward the end, bubbles were few and far between, and much smaller. Instead, the coolant flowed smoothly up and out of the filler neck.

At this point, I put the rad cap back on and fired it up, letting it idle for about 10 mins as I watched the overflow valve. Nothing. I took it for a quick drive around the block (sketchy - no plates!), and then more idle, and again around the block, and again another 10 mins of idling. The temp gauge rose a bit, but the fan would obviously kick in and drop the temps again. It hovered roughly just below the middle of the dial.

Finally, I shut it off and listened for the tell tale gurgling in the expansion tank...nothing. No coolant going into bottle. No hissing or bubbling.

So, I am cautiously hopeful that I've solved the problem. Basically, an unbelievable amount of air came out of the cooling system tonight - I'm sure enough to cause some nasty air locks. I'll check again tomorrow, top it up again as Wayne suggests, and hope for the best. The real test will come when I insure it and start driving it around town, but for now it's looking good.

Thanks for your advice all.

Robin

 

[crushers]

check it cold every morning for the next couple weeks and add as needed... these are a bugger to get all the air out of...
here's hoping for the best...

 

[harveya]

As wayne siad, keep an eye on it. The Big bubbles sounds like trapped air working it's way out. If it was the head gone, I would have expected it to carry on and pump out like it was being pushed out by a pool pump - very fast and not stopping even when the engine warmed up. As has been said the engines are an absolute dog to get all the trapped air out of, once it is out you are good to go though.

One thing to check at some time, often the trapped air is caused by the water pump being worn and the metal being pitted. If the trapped air comes back I would check the water pump although it is a PITA to do - 4 hour job abd while you are at it you can change the timing belt as it has to come off anyway.