Water system modifications.

Forum: 

I've had enough of the water system on this truck and am thinking of making a few improvements.

Was thinking of going to a constant bleed system like most modern cars have. (I've done this on my 1967 triumph, so i don't see why i shouldn't be able to!)

Basic idea:

Remove rad cap from under passenger seat.
Weld or braze a flat disc over hole.

Connect that bleed, and the one on the heater line to a new, modern, tank. (will probably put a small restrictor in each line to reduce flow.

***Question***:
Best place to fit the return from the bottom of the new tank? Half inch hose and needs a draw/pull on it?

Advantages:
1) Self bleeds so no air locks so any problems immediately visible at tank water level.
2) Easy to fill. Remove cap, run engine and keep topping until water level settles.
3) No crappy caps or badly sealing pipes
4) Easy to fit. less than a days work start to finish

Anyone see any disadvantages or something glaringly obvious I'm missing?

Thanks,

Jon

Assume this is a Hi-jet. Had

Assume this is a Hi-jet. Had one for a short while (1998 S reg 1.3) and water circulation seems to be a problem.
You don't fill the expansion tank under seat but the rad behind the front grill....which the clips break off with age hardening!!
Your idea sounds interesting and hope its an improvement.

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Current- 04 Silver YRV TURBO
Past- 91 Charade GTti, 89 Charade GTti, 98 1.3 Hi-Jet.
A friend in need is a friend indeed, a friend always in need, an Effin nuisance Wink

Quirky!

I realise the system is a bit of an odd ball, but it does work perfectly well if you don't have any other issues. If you are having issues with the system, you would be better to find the true root cause than anything else.

I too have thought about the pressurised header tank method conversion, but truth is I only thought about it while I was having problems!

I tend to start with a drain down of the system, then I pressure test it with a butchered tyre valve and pipe into the bleed nipple under the drivers seat. I put a brake hose clamp onto the expansion tank pipe, then I charge it up to about 20 psi with a tyre pump.

I then fill a squirty bottle with some soapy water and cover all the pipe joints, radiator, caps, hoses etc with soapy water and watch for bubbles.

They often leak at the rad caps, the little hose on the back of the head near the inlet manifold and cam sensor, right across the bottom of the radiator, and the hose clips on the bottom of the radiator corrode and go weak.

The next very common cheap component that is the achilles heel of the hijet is the bloody thermostat - and housing. The thermostats stick closed, even new ones. Why I don't know, but if you buy a new one test it in a pan a few times before you fit it. The thermostat housings are plastic and often crack too.

At the same time, if its been overheated a few times, and even with new rad caps and a successful pressure testing result, it still purges and looses water, then the head gasket has gone.

If you've just bought it and its full of radweld/kseal/etc in the coolant, more than likely it been overheating for some time now and more than likely the head gasket has gone. The always go on the rear cylinder on the exhaust side from what I've seen so far.

If you need rad caps, make sure you buy "First line FRC74" caps, because from previous failed purchases they are the ones that fit best.

I have had to type this sort of stuff out that many times that I sat down one night and wrote an article on my website about it, it might help you, it might not, but alot of people fail to fix their overheating hijet and flog it on ebay in the end! http://www.daihatsuhijet.co.uk/hijet-overheating-problems-head-gasket-or-not/

Best Regards,

Matt

Http://www.daihatsuhijet.co.uk
For Hijet manuals and information