Strange coolant temps

[vstrom]

Hello,

So, recently I changed my thermostat and block heater. The thermostat was changed because it didn't seem I was getting enough heat; I had to do it twice since the first replacement decided not to work. I changed the block heater because it failed.

I then drove 950km from Thompson Mb to Saskatoon to pick up my wife (she's in college there). Temps were between 50% to 55% (about a needles width highter than the middle) according to temp gauge. City driving in 'Toon the gauge rarely got above a quarter which I believe is about normal for this diesel.

Then we drove home.

It ran normal for just over half the drive. It was around the point were I switch from my spare fuel tank to the main tank that it started to run hotter.. around 75%. I'm not sure exactly when since it would have happened with a driver change/ dog walk. It stayed consistently at 70 - 75% all the way home.. never close to the red but definitely different than normal.

Ok.. so the next day we decide to drive into town for grub. It's 25 minutes of highway to get there, against a big wind, and the temps sits at about 45%.. which seems about right. We come straight home, with the wind, and the temp hardly gets to the 25% mark. I understand the engine wouldn't be running as hard while driving with the wind, but it should still get up to it's operating temperature.. especially when it doesn't have as much airflow going through it.

So.. I'm not too sure what to make of this. If it would be consistently wrong one way or the other than I could probably make sense of it. I'm going out right now to see if I can burp anymore air from it then maybe a test drive. I have to drive my wife back to 'Toon in a few days and we need to be able to depend on this sucker.

Thanks.. any info, speculation or wild ass guesses are welcome.

[Mr. Flibble]

Your idea of burping extra air from the system is a good one - it was my first thought.

You could also have calcium build up that is restricting flow. And finally, different driving conditions do have quite the noticeable change on the engine temp. I have had my thermostat close in my L400 while driving highway speeds. Granted, I was in the Kootenays descending towards the Okanagan Valley in -20 weather, so the engine was not working hard and it bled off all the excess heat through the radiator to the environment.

[nxski]

25% generally is operating temperature and anything over 50% is reason to pull over and let the engine cool down.

[TardisDeli]

Hi. don't drive it. L300 needle should be less than a third. Over halfway means stop and idle the engine in neutral, in a breezy spot, to cool it down. 3/4 high means engine damage imminent.

Is your expansion overflow bottle good (they get little cracks and leaks with age). Ensure the fluid is exactly at the full line when cold. Yes it is hard to see, lift out the bottle, mark line with a felt pen so you can see it with a flashlight shone into the bottle once its back in place. Or my favourite idea is keep a chopstick in the glove box, mark on it what the high low heights are, so you can just dip the chopstick in the overflow tank. Mine was overheating a bit in summer, but Butch CVI said my coolant level was low, only needed a half litre of coolant added to make it exact to the line and suddenly the temp guage was happy.

When engine and coolant cold, undo the radiator cap, should hear tiny hiss as you undo the cap (vacuum seal). Coolant level should be near to the top. Poke your finger in, feel the metal fins, should feel smooth, if you feel grit, then you have the calcium buildup, which clogs the fins. Declogging fins is difficult: Can try to soak it overnight in vinegar, then rinse it and refill with coolant; or get it professionally done --- note that newer radiators have plastic tops so your original radiator is much better if all metal so dont let them rebuild it with plastic.

In winter, shouldnt be overheating that much. Overheating is the single worst thing for a delica, small engine size so it will warp and crack. Check your engine oil, dipstick, and let a little out of the drain plug on the bottom of the pan; ensure no coolant in there, Bad news if so.

Let us know what you find. Christine.

[bionic]

yup, sounds like the classic symptoms of retricted flow. If its not the rad, then its likely to be in the head itself. (my last L300) A dying water pump, or drive belt has similar symptoms, but is less likely. Check the coolant level, note any changes. Check the engine oil for signs of coolant. And lastly check if your blowing a little "white" out of the tailpipe. Hairline head cracks will show up the same way. Look for signs of leakage outside on the block to head seam.
Steam/air in the head can cause erratic temp readings. (again//bad headgasket/warped head or cracks) All of these are easy to check yourself in around 10min. If you find nothing, then dig deeper, perhaps with some professional assistance.

[Firesong]

Lol
Everyone jumps to the horrible scenario. With a proper thermostat mine runs in the middle of the gauge.

If there is calcium buildup go to a shop and ask for flush. Might help. Then you will get fresh coolant.

I also run with some cover over the rad in these temps. I am in Saskatoon. The winds you hit are hard to explain to non prairie people but they will warm up the engine.

Do you get any cabin heat? If you have high buildup I wonder if your heater core would naturally be plugged up.

I'd recommend the flush and go from there.
FS

[vstrom]

So an update..

Took off the rad cap and I haven't lost a drop. Squeezed the lower rad hose a few times to see if I could burp this big baby, then started it up. After a few minutes I cranked it up to about 2500 rpm (or i'd never get the coolant even close to warm) .. and once warm-ish ran the heaters on and off a few times. Did this for about 5 minutes the shut down the dog and pony show. I'm not really sure if I managed to get any air out or not, but there's no indication of a cracked head. No white smoke, no leaks around the head.. I did have a few drops at my rear heater where the previous owner T'd off another coolant line to go to the rear fuel tank (it's part of the WVO package). I tightened them up. Let the oil cool down for an hour then checked the dip stick.. nice oil almost due for a change.

So we then drove to town to do a few things. It averaged around 30% on the way in.. seemed to run cooler at 100 kph and warmed up to 40% at 70kph once we hit town. Weird.
Coming home it seemed to stabilize around 40%.

So.. weird.


I get plenty of cabin heat.. earlier this winter I flushed my heater core when I changed my thermostat. I personally think I need to get a complete flush.. my rad does have a fair bit of calcium built up. Unfortunately, i'd have to get that done in 'Toon or Winnipeg.. no one I'd trust here to do it properly.

I appreciate everyone's input and I know that these vans are prone to head cracking.. but I'm leaning with Firesong with this one. In fact, I'm almost glad that it moves around.. let's me know that it's not a fake gauge that doesn't do anything like on some cars! When it was at 75% I would check the defrost on full and it wasn't that much warmer than normal.. and the needle is still in the 'normal' range.

Anyway, gonna check everything again tomorrow with another test drive..

Also, Firesong if you know a reputable mechanic if 'Toon that can do a full flush on a Deli and not charge an arm or leg, and is available on short notice (Monday or Tues) could you let me know? Thanks

[bionic]

Lol
Everyone jumps to the horrible scenario. With a proper thermostat mine runs in the middle of the gauge.

If there is calcium buildup go to a shop and ask for flush. Might help. Then you will get fresh coolant.

I also run with some cover over the rad in these temps. I am in Saskatoon. The winds you hit are hard to explain to non prairie people but they will warm up the engine.

Do you get any cabin heat? If you have high buildup I wonder if your heater core would naturally be plugged up.

I'd recommend the flush and go from there.
FS

I agree to start small and work up from there.(read the first response) however, I have owned 3 of these vans (L300) and only the one with the restricted flow in the head ran at mid gauge. (even with the lower 192' thermostat) I will state though that the gauge is just that - a gauge. Its not 100% accurate, and only reflects what it sees at the sender. Sure, do a bleed, it can't hurt. I have yet to see a Delica L300 have a working front heater and have air in the system as the front heater sits higher than the engines head.(L300)
Anyway, do an external temp reading with an infrared thermostat at the upper and lower hose to see if there is a restriction there. It will at least iron out a few variables and should cost nothing. Best of luck..

[Firesong]

Best mechanic :) is recovering from a knee operation in dauphin MB. Contact Manitobadeli here on the board for advice.

[vstrom]

Eventually I'll have to drive down there and get a tune up.. I've been chatting with MbDeli on and off since I got my rig. It's good to know I have an expert relatively close!

Van seems to run normally.. temps around 35%. Tend to climb abit once I hit town and slow from 100 to 70.. it's slightly confusing to me. Once summer hits I'll be able to park it at work and rip it apart to tinker around.

Thanks for the help guys.. I'm sure Ill be asking more again soon!

[mararmeisto]

If I remember correctly there are two thermostats available for the L300 engine: 82 deg C and 88 deg C. The lower temperature will give you a normal reading at the lower third line, while the higher one will give you a half-gauge reading. Neither is bad for this engine.

Water temps over boiling are a problem because then you don't have water in the cooling loop, you've got steam: water good, steam bad.

Of course, if you're driving one of the new sleds, then I'm not certain what the thermostats might be. That being said, water still good, steam still bad.

[FalcoColumbarius]

If I remember correctly there are two thermostats available for the L300 engine: 82 deg C and 88 deg C.

Typically, 4D56 in the Delica is the 82° thermostat, the 4D56 in the Pajero is the 76.5° thermostat. Often when air gets into the system an air bubble will lodge into the thermostat, ergo creating an insulating cushion around the paraffin device that opens the valve. This can consequently cause the motor to run hotter. I have been learning that "heat being power", it's not necessarily better to go with the 76.5° thermostat in a Starwagon. I have seen thermostats with a little hole drilled into this centre part where the bubble is most likely to lodge, with a little rattling rivet (with the shaft end crimped once inserted) that jiggles the bubble through the hole. Last time I was at CVI they had a 76.5° thermostat with this feature in it. I've tried the 76.5° thermostat but have found that the 82° one works better for the Miss Lil' Bitchi. My current thermostat does not have the hole & rivet feature, maybe next time. The important thing, really ~ is to make sure that any air is exercised from the system in the first place when replacing the coolant. Here is a link to how I do it, if you're interested.

Falco.