Delica Canada | Mitsubishi Van Club

Hello all,

I hope I'm posting in the right location but I just did a simple air filter swap (part number 4810) on my l300 and went cruising about to test it out. After the engine got to normal operating temps, we felt the heater air get cool on light to normal throttle and thats when I looked at the temp gauge which was on the high side right below the red tick mark. Being concerned we headed back home and it would fluctuate from back down to normal mid level, then back up to the high side and the heater would again spit out coolish air. Its almost like when you have air in the coolant which I've had on another vehicle but I haven't touched anything else.

I double checked to make sure I have the canister latched on correctly and the little tab lined up with the slot, then the two buckle clips. Tomorrow I will throw the stock one back on to see if fixes the issue but why would just a higher flow filter cause high temps? It should lower them right?

Also have my EGR blanked if that is any help.

Thanks

The two are almost certainly unrelated, unless you were aggressively testing the vehicles extra power?

The engine temperature fluctuating that quickly, and the heater being cold, suggests air in the coolant- I would guess from a blown head gasket pressurising the cooling system and pushing the coolant out. Definitely check your coolant level before driving anywhere else, and once topped up check that it's not bubbling when the engine's running.

A lower restriction filter should, in theory, reduce the heat output of the engine and EGTs, but it would be difficult to see that in the temperature gauge as the water temperature is controlled by the thermostat. It might take a fraction longer than usual to get up to temperature is all.

Yeah I couldn't really find a reason why the filter would cause heating issues, it was just weird that that was the first time it happened and within an hour after the install. I'll check the coolant level today when I get home, I took it to work today and levels were back to normal with the K&N but I didn't drive far.

I wasn't pushing it really, and the funny thing is the more i did accelerate the temps would come back down and blow heat again. I didn't mess with the injection pump but is there a possibility that the engine is getting too much air and not enough fuel to match it and detonation is happening?

Thanks for your help.

Nope. Diesels don't really care about air/fuel ratio. If there's more air than necessary they run cleaner, and your Exhaust Gas Temperature drops. Less air than needed makes black smoke and raises your EGTs. Diesels care more about injection timing and, in extreme cases, cylinder temperatures, but neither of those should have changed that drastically.

Good to know, well ill check the coolant out here in a few hours, if I'm seeing small bubbles (like pin head sized ones) compared to a rolling boil type am I safe, or still thinking blown head gasket?

I'll report what I find.

Thanks

So I checked the coolant and although I thought it to be a bit low, there wasn't very much activity when I had a pool of coolant in a narrow funnel while idling. Topped off the coolant and switched the air filter back to stock then drove around. Temp climbed again and then dropped back down rapidly.

It seems completely hit or miss, I don't have any white smoke jetting out the back, or what appears to be water/coolant in the oil. We took it up in the mountains not too far away yesterday and on the way down, the temp got high (never hitting the red but about two needles widths away from getting there) and camped in pretty cold conditions to test out an inline diesel fuel heater I installed (which worked great, started in 28 degrees F). When we came back, it was a cooler day by about 20 degrees and I actually was pushing it a bit harder with no problems. Power was good, temp was in the middle and never moved, and the heater was blowing fine.

So two things I want to check before getting into the head: Temp sensor and Thermostat. I've never been able to start the van in coldish weather IE anything below 32 degrees F and I know that temp sensor controls the glow plugs as well. A stuck thermostat (that might have been shocked when we took it up in the mountains) may explain the variations of heat then back to normal cycles as well.

Anyone have those part numbers? I am happy to buy the OEM ones as well.

Thanks!

PS Growlerbearnz, I'm following a thread you are commenting on with Morgonzo and his overheating issues, you don't think the two are related do you?

It *might* be a faulty temperature sender. I'd be lifting the engine bay cover and feeling the top radiator hose at regular intervals to learn what "normal" feels like. The difference between a hot engine and a normal/cold one is quite noticeable. Find the genuine part number here https://partsouq.com/en/catalog/genuine ... Mitsubishi, and then throw that into Google to find equivalents. It's a fairly common part, used on many engines.

A sticky thermostat sounds possible- the bit where your engine overheated while going downhill suggests a thermostat that had closed, and then stuck closed. Most other causes of overheating would have shown up while driving *up* the mountain.

4D56s can blow a head gasket without letting water into the oil. A cracked head would also let gas into the coolant without contaminating the oil- but a cracked head or blown gasket would also show up more when driving up the hill, not down.

Growlerbearnz wrote:Nope. Diesels don't really care about air/fuel ratio. If there's more air than necessary they run cleaner, and your Exhaust Gas Temperature drops. Less air than needed makes black smoke and raises your EGTs. Diesels care more about injection timing and, in extreme cases, cylinder temperatures, but neither of those should have changed that drastically.

I'd heard that if you have too much air the engine runs hotter, if you have too much fuel it can run hotter ~ that there is an optimal range where the oil/air combination produces the ideal heat/power ratio. I heard this from my buddy the VW/Audi/RR mechanic. Perhaps I should ask him why again ~ I just remember this discussion when I was tooling with my fuel screw.

Falco.

That's true, if you're wildly off the scale in either direction you can run into trouble. Still, a diesel's air/fuel ratio is in the range of 30:1 down to 15:1, and a K&N doesn't change the ratio *that* much.

Well, bit of an update. I drove it all day Sunday and today and no issues. I'm keeping a close eye on the temp gauge and will check to see what normal top rad hose feels like to the supposed high temp reading. I ordered the thermostat first, which should be here next week. Keeping my fingers crossed as I would like to wait till the spring and nice weather for a head gasket/timing belt replacement job. I doubt the head is cracked because we have a pyro meter set to alert us if we exceed 850 F. I'm not sure what the bad range is but I keep hearing anything into the 900 degrees Fahrenheit is getting too hot. The gauge is tapped into the dump pipe manifold so I'm sure thats actually higher than whats going on near the head. Anyone have thoughts on this?

Thanks for all the good info, I really doubt the K&N filter is the issue, maybe it allowed a bit more power to push a problem out from hiding, not sure but I know it's not the real issue.

Thanks

roddamusprime wrote:I doubt the head is cracked because we have a pyro meter set to alert us if we exceed 850 F. I'm not sure what the bad range is but I keep hearing anything into the 900 degrees Fahrenheit is getting too hot. The gauge is tapped into the dump pipe manifold so I'm sure thats actually higher than whats going on near the head.

Exhaust gas temperatures measured post-turbo (dump pipe) are usually 250-350F lower than pre-turbo (exhaust manifold) temperatures. Our turbos can handle 1200F *pre-turbo* indefinitely, and 1400F infrequently- so your warning of 850F post-turbo is about right. You should be able to run at 850F indefinitely, but the occasional, brief excursion to 1000F should do no harm.

As for the head cracking, I suspect it's all about how quickly the temperature increases rather than maximum temperature. Anecdotally (and I know that the plural of "anecdote" isn't "data") 4D56s that haul large loads and tow things are fairly reliable, despite running high EGTs all the time. Cracked heads seem to happen more to vehicles used around town and off-road- I suspect because they're idling a lot, followed by bursts of power. It's just a theory though.

Growlerbearnz, you're legit. Okay, all good info to know. Well, I might need to chalk it up to the car gods but all is back to normal. No temp fluctuation or loss of power (the opposite really, I think that k&n filter is doing well) and I've been driving consistently with varied grades and distances. No strange bursts of power as we use it for DD. I'm at 194,000 km so its high time for a head gasket/timing belt job soon and have a few plans to swap on a bit larger turbo td04-12t i think is the code. The 02-07 WRX turbos.

I planned on a larger, more efficient radiator and oil cooler and not intercooling but keeping boost levels lower which I feel will allow more volume but with less strain on the motor. Also the extra cooling from the rad and oil cooler.

Again, I'm new so if im getting off topic or something and violating rules let me know. I tried searching this but get a lot of varied answers.

It's a good idea to stick to the TD04 range as the turbine size is perfect for our engines, but beware of over-sizing your compressor. T-trim compressors (The "T" in "12T") tend to be most efficient at higher airflow levels, which is a bit pointless on our low-revving torquey engines. You'll get a more responsive engine if you stick to a B- or G-trim compressor ("09B" or "13G") which is more efficient down low, just like the rest of the engine.

http://www.delica.ca/forum/viewtopic.php?f=102&t=17650

Great info, so we are running the 09B stock, and I'm looking for a bit more power on the highway (with an inch larger tires to help top speed to get to 70mph) and maaaaybe thinking of pulling a small fiberglass trailer like a Scamp or something very light weight would this opiton be better: "Now the 13G chart- at 4000rpm we can make 20psi safely. Set wastegate to 20psi, and now we have 20psi available at all RPMs. Much better. "

Or would you try to increase boost to say 14psi on the 09B instead? I never really go past the 3-3500rpm range as I feel it's pushing the engine a bit so that would be my sweet spot for crusing and I would be willing to sacrifce a little low end power for more top end.

I was hoping for the 110-115hp range if possible.

Thanks

I think you miss understand something. If you have a higher volume turbo but keep the psi low, you won't be able to push more oxygen molecules into the combustion chamber. You can either cool the intake air ( make the air denser) or increase boost pressure.
I assume you already opened up your exhaust. That's much easier, cheaper and safer for your engine. Personally I would not go over 15psi. Just my humble opinion. Let me know if I am wrong.

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