Testing L300 head

[shmope]

Hello Delica world.
I have a 93 l300. I am suspecting a blown head but would like to test it before pulling it off. I have tried a radiator co2 test multiple times, all came back negative. Even tried with thermostat removed. I have access to glow plug and injector compression test fittings and would like to know what readings I should expect for both good and blown head.

My reason for suspecting a blown head:
Morning before departing for a 1000km trip, fully loaded, over mountains, in cold weather, the overflow tank spat coolant after starting up and stopping briefly. (I stopped the engine as I wanted to check fluids before leaving, thats when I noticed the coolant coming out of overflow. It was -6c)

About 700kms through the trip, after multiple mountain passes, the upper rad hose blew on a flat section with no sign of over heating.
I replaced hose, rad cap (montero cap, had same psi rating on it), and filled with fluid. I then drove it around for a bit, up steep hills, took to a mechanic for a quick look, all seemed ok. Slight pressure build up in upper rad hose had me concerned. Had to press on, it was -20c.

Last 300km over a few more mountain passes, no overheating, slight pressure build up in the rad hose. Made it to my destination.
After letting van sit for an hour or so (-15c), I started it up and drove down hill to my house. Half way there (5min or so of driving) I noticed the temp just above half. I turned engine off and coasted down the hill to my place. The engine seemed hotter than normal.

I noticed coolant leaking under the van, probably from the water pump, I have checked all the hoses.

I have since removed the thermostat and tested it, looks fine. Ran without thermostat and drove around for awhile in 4x4, no overheating, didnt even climb above th C line.


Reasons these things could have happened?

I did open the rad cap when hot a few days prior,which dumped some coolant into overflow and may have created an air pocked in coolant system?
The water pump and belts are over 100,000kms now. Maybe worn seals? Drawing air or loosing coolant?
Air lock in coolant system?

I will be replacing the timing belts, water pump and seals regardless and will replace the head if necessary at the same time.

Do I need to remove the crank shaft pully in order to remove the lower timing belt cover? I think I have all bolts removed but it still will not come off.

Running the test this weekend. Will post results.
-Shmope

[siemens8]

replace the thermostat. Washer is mounted through the key on the receiver and bolt of 2 x. often hard to shoot the washer, you have to knock.

[philmeup1]

I've read on here that sometimes the radiators on these things can be problematic. I too have a '93 which is getting up there in age. Even if your van has low mileage, depending on where it was parked and the conditions over in Japan, the rad might be gummed up from the inside. Maybe the coolant is not flowing properly due to this?? I've not had this problem with mine but it would make sense that there could be a rad issue with a vehicle that's over 20 yrs old.

If you're not seeing coolant in the oil and you have no loss of power, I'm going to say probably not the head. Now I'm just a wannabe mechanic at the best of times. But after reading lots of great posts on here, and having a somewhat decent understanding of how things work, I'd check your radiator.

The other thing I always do religiously is warm up my van before driving it. Even in the summer and especially in the winter. The head and the engin case are made up of two different metals which heat up at different times. Replacing a head is expensive and wayyyyy beyond my skill set. Bought my van with 71,000kms on the clock and now up to 96,000kms with no problems. I'm going to try and keep it that way.
Good luck with the repair. Phil

[helibrian]

do you have coolant in your overflow tank? I've noticed when my engine gets hotter than normal I have to add more coolant.i think I had a small leak that I had to add fluid once or twice a year. you don't have to remove the camshaft pulley to remove the bottom cover but you do if your changing the seal.

[shmope]

Thanks for the replays

The rad looks new. The head was replaced a few years ago along with the rad and other main components. I've pulled the thermostat out already and will replace when I change the water pump and belts. Just need to count the teeth on the lower belt before I order.

I'm not seeing any coolant in the oil at this point.

I'm going to run compression tests soon.

Any ideas on what readings I should get?

[Rattlenbang]

As far as compression tests go, just google diesel compression readings and you should get a ballpark. Problem with these heads is when they go hey often go intermittently as they start with just a tiny crack that seems to open and close. I knew my van needed a new head and yet drove around more than a month before finally saw grey smoke and loosing coolant. So a compression test might not show it. boiling over after just starting, plus other cooling issues suggest to me head issue.

[FalcoColumbarius]

I'm going to run compression tests soon.

Any ideas on what readings I should get?

Take a look through here: http://www.delica.ca/manuals/L-300%20Ma ... engine.pdf

That link can be found in "L300 Dedicated Category Reference Forum", which is in Delica Canada Technical.

Falco.