Preventing blown head gaskets

[ntmokey]

So I've researched and lurked long enough to know that blown head gaskets are a major problem on the L300. I've read the horror stories, the repair threads, and spotted the ads for high-mileage L300s with head gaskets already repaired ... or in need of repair.

But is there any way to prevent it?

I have 1990 with 150,000 km on its way over from Japan right now, and I'm already planning preventative maintenance for when it arrives. Is there anything I can replace that can help mitigate the risk of a blown head gasket down the road? Barring that, are there some driving tips I should be aware of?

From the research I've done so far, I'm planning to do a coolant flush, and take it easy letting the engine warm up whenever possible. Any other ideas?

[Lapprentis]

Since it seems to be related to overheating, the first thing I suggest is to put an EGT Gauge so whenever you are climbing a hill, just make sure you stay, by easying your gas pedal, under 1000C. Even on the highway, on what appear to be flat but is a long soft up hill slope, it is easy to get to the point where you are injecting diesel (heat) without going any faster....

Beside that, have cooling system checked regularly so every components are working properly

Lapprentis

[FalcoColumbarius]

Hiya Ntmokey, Welcome to Delica Canada

I have owned and operated my '92 Starwagon for over eight years, she will be twenty-four in October of this year. I'd say the important things to remember is not to forget that you are driving a diesel and not a petrol combustion engine. Unlike a gasoline engine, which typically has a compression ratio of about 8:1, 10:1 ~ the 2.5 litre 4D56T Astron engine has a 21:1 compression ratio and an aluminium head. If you drive your wagon like a Ferrari or "like you stole it", you are going to come across issues. Typically I warm my wagon up until the water temperature needle moves. This means that the thermostat has opened and the engine is more or less at ambient temperature, which is what all the bolts are torqued to. This process takes about four minutes and I do it every time I first start the engine outside an eight hour period, depending on the weather. If you start your engine first thing in the morning, rev it up, spin a few donuts &c., you're going to screw your engine.

When climbing a hill keep your revs high, watch your temperature and remember that you are driving a truck. Changing out your fluids is important, as well. Oil change every 5,000 kilometres; your coolant gets stale over time and loses effectiveness in the various properties of it's functions, not only to transfer heat the radiator but also to prevent galvanic reaction between the cast iron block and the aluminium head. If the there is a reaction between the two ~ the iron block will win, the aluminium head will lose. I change my coolant no later than two years and use Hepu G11 @ 40% coolant to 60% distilled water. Don't just grab any old coolant because they are all formulated to different galvanic proportions, for instance; the G12 coolant will eat the head of an Astron because it's formulated to perform with different metallurgical properties.

Hope this helps... smiles.

Falco.

[Growlerbearnz]

"Mechanics hate him! [#locationdata] man discovers one weird trick to prevent head gasket failures!"

Ok, sorry, too much looking at trash on teh internets. I agree with the others: overheating is what kills most head gaskets. An overheated aluminium head expands too much and crushes the gasket, which then gradually fails. Ever noticed how head gaskets mostly fail in between cylinders? I believe that's because there isn't much coolant in that area, and aggressive use of the accelerator loads that area up with heat quicker than the metal can conduct it away. When driving, I try and look ahead and plan when I'll need more power, then ramp it up gently to give head temperatures time to equalise.

Oh, here's the one weird trick: Re-torquing your head bolts 5000km after installing a new head gasket, or after a serious overheat, is an old-school way of preventing head gasket failures, but is controversial when applied to modern gasket materials. I do it and haven't had a failure yet, but your mileage may vary. Basically I loosen one bolt a quarter turn, then re-tighten with a torque wrench. repeat for each bolt. When I do it at 5000km it usually takes about a half turn to tighten to correct torque again.

[ChuckBlack]

Good tips FalcoColumbarius! A blown head gasket is definitely a sign of improper PM or just plain simple bad luck! All of the above (FalcoColumbarius) are correct in regards of eng temp. Installing an EGT gauge and have it in pain sight is a no brainer! Keep it under 1400F at all cost, and maintain your cooling system for god sakes! Regular fluid checks, as well as ongoing preventive maintenance will help your wallet and your Van in the long run (perhaps your wife as well). I've got a Madman multi function gauge in my Delica which indicates, engine oil pressure and temp, boost, EGT, charging and battery Voltage. In my opinion, the more you know, the better you understand what's going on under the seat!

Did my spring clean up today... Damn, what a nice van!