Hats off the Head's off. Hijet cooling system catastrophe.

So i got it off. Gaskets gone. What bothers me is the way the gasket is designed. The channels for the water are much bigger than the tiny holes in the gasket.

That is also where the problem with my gasket was. On the water channel where the gasket fused there is also a spot where the water went under the gasket and built a lake underneth the gasket. It in my opinion because the water has to go through the tiny hole in the gasket while the channel is much bigger. look at the pictures and a pic of a new gasket and lay it over. Its ridiculous. Vicious enginers. This was designed to fail. I will properbally add some extra holes to the gasket so more water can flow. The new gasket looks exactly the ame. I am shocked

Or am i stoopid and somebody has an explaination why the gasket silouette doesnt fit the motor design.

The brown stuff on the gasket show the silouette of the channel. See how small the hole in the gasket is where all the water has to go through. FAIL




this is where water entered the cylinder asumingly


damage to the block because of bad gesket design



zoomed out of damage ... maybe it will be ok because its not a sealing surface.
this dent can not be skimmed. its too deep.

Is that piston cracked or is it the photo?

On other engines which have had block face corrosion, I have cleaned it back to bare metal then filled the hole with chemical metal, then flattened it back. You could lead fill it too.

Gaskets normally have small water jacket holes, it evens out fluid movement across all cylinders is my guess.

HighlyJetted wrote:Is that piston cracked or is it the photo?

No i think its not cracked, just a scratch. Bit unfortunate cylinder one is in full kompression. Cant see the cylinder walls. I didnt want to spin the engine but maybe will do tomorrow.

HighlyJetted wrote:On other engines which have had block face corrosion, I have cleaned it back to bare metal then filled the hole with chemical metal, then flattened it back. You could lead fill it too.

Good idea the chmical metal stuff can take temps up to 300c as  i read. I found some elring curil t in the garage. but that stuff stays liquid. maybe the 2 component epoxy is e better idea.
Lead would be nice.

HighlyJetted wrote:Gaskets normally have small water jacket holes, it evens out fluid movement across all cylinders is my guess.

Yeah as i was looking around i saw most other gasket designs have small holes instead of matching the channels, there must be something about that. But hmmm i think its questionable. The channels on the other side of the cylinder are matched exactly.

Clean the deck up real good first.
The location of the corrosion won't cause any real problems.
That head gasket is really badly gone, must have been eating alot of water for a long time.

Yes. Its sad. I hope i will get it working again (with the old head)

If you have access to a tig then you could pool some extra metal into those divets. File carefully, glue some wet an dry to a sheet of glass and hone it all true again. Make sure you turn the block about 30 degrees on each stroke and don't try and remove every single pit. You just want to remove a few microns and get the surface true again. I had a head gasket go three times on me and all the garage wanted to do was fix the head. I fixed it myself by sorting the block with the same method and not the head which was absolutely fine. I could have skimmed it on my mill but that would have been complete over kill. But you would have to remove the block of course?

Jahaha i ll sort that for the next time. For now we tried to get away with a tiny drop of gasket paste. The head came out better then i thought but the block had some badass corrosion close to the fire rings. time will tell.

You did skim the head right?

No. Maybe next time if it fails again soon. I did a test drive yesterday only 20 minutes but everything worked. I noticed that the hoses had become much harder then ever before?!?!
But nothing was purged into header tank und fan kept her cool after a ride and then ideling in the sun.

I only tightened the cyllinder head bolts while motor was cold to about 60Nm
I have to tighten the bolts again today after another ride when motor is hot, dont i?What torque you suggest. Manual says 59 - 63 or something. I am a bit puzzled about that.

It takes around 10 heat cycles to fully bleed the coolant system properly.

Then if you make it to 1000 miles of mixed driving with water level stability you know its fixed for now!!

I tend to set my torque wrench to about 65Nm, for all its worth. They are not all that accuate anyway and cleaness of threads etc make a massive accuracy impact.

Truth normally occurs when the vehicle has been battering down the motorway at speed, then it hits stop start traffic tailbacks for a few miles. Any hijet owner gets a twitchy bum and stares at the temperature gauge with nerves!!

do you change the bolts every time?

No, I re-use the bolts. But I do clean all the threads and holes to perfection.

Thanks for confirming. So i will give them the missing 3-5 nm after work tonight.

FYI some of the last pictures before we reassembled:

BTW FYI 700km later and HiJet is still going strong. Knock knock.

Changed differential and transmission fluids and started the body work. Not too much jet. Removed the daihatsu brooch and applied filler and primer in some places. Varnished the bumbers. Still lots to do but damn rainfall. I have to clear the garage if it doesnt get better

Just an update: Still running smoothly. Rear and front window rust removed and fixed, sliding doors rust removed and fixed, impact body work done and shes been freshly varnished. Cavity sealed with fluid film and perma film. Decals ordered...

Also got some new old rims to sand blast them at a friends garage on thursday wich is my day off. My bridgestone 713s are perfect but I want to have proper summer tyres. I drove 70km and payed € 80.- for the rusty old rims.... at least sand blasting will be free.

What decals and where did you get them. Was wanting a set of the originals to put back on, side strip, front bonnet and rear door. Prob have to get them made up.

Actually i only ordered some stickers to put them on. My bus is completely white right now wich . Dont know if the oroginal decals can be ordered from daihatsu. I would like to have the original hijet sticker from below the front window, too.

I plan to put this one on the front where the daihatsu sign used to be just for fun:

Doubt Diahatsu have them, may need to get creative and get some printed but will need good quality photos of actual ones to work from if anyone fancies taking some with dimensions.

I have been doing 10.000 miles with the repaired Motor now. I have had no further repairs and i am pretty pretty satisfied but now i have oil leakage. Its just a tiiny drop here and there falling from the clutch housing.

I think it might be the shaft seal but i have not investigated any further.  

As MOT is urgent i will have to repair it....



PS.: I have repaired it.... The cylinderhead cover had come loose and the oil filter, too.