Flushing the Hijet

Hi it's me again. Ive fixed that rusty coolant pipe. Used that brilliant epoxy stuff and reseated it as recommended by you brilliant folk on this brilliant forum.

I'm gonna flush and re fill now. How many litres of anti freeze do you think I should need and also am I to mix it down with water?

Many thanks.

Ive opened up the little plug beneith the radiator and let the water out. I opened up the cap ontop of the rad and more water came out. There is still water in the expansion tank though...

And also... is this really how small the dipstick is supposed to be??

To flush it properly i would take off the radiator and the upper and lower hose from the radiator and pour lots of water throug it. There are also flush additives that are to be used as stated on the labels. Clean the radiator seperately.

To refill take both caps off. Refill untill water overflows under the seat. Put the cap under the seat back on and fill up the rest. leave radiator cap off and let the car run a couple of heat cycles and top up again.... massage the hoses... top up again.... finally put pack the radiator cap. It helps if you tilt the car a bit up. For example put the front wheels on the sidewalk.

For coolant: Take the pink stuff. Check the bottle for mixiing instructions. Normally you mix it 50/50 with demineralized water.
Apart from that there are ready to use mixtures.



I think you will need about 3 to 4 litres of coolant. Not sure. Also refill the expansion tank .

Dip stick looks fine to me.

Thanks for the help there. Just to clarify before i proceed, am i to take the actual radiator out ? Went and got some ready mixed pink coolant and my drive is on a bit of a hill so thats good.

You are welcome.
Leave the Radiator.
Just refill.

I forgot to mention earlier you have to also bleed the heater matrix.
Leave the rubber cap off from the beginning untill it bleeds and then put it on.
Stick to the bleeding guide from board member HighlyJetted if unsure.

I try again

To refill: Take off both pressure caps. Refill untill water overflows under the seat. Put the cap under the seat back on. Fill up the rest at radiator. Dont put cap of the radiator back on jet.
Start the car with heater temperature on Max. Take off the rubber cap from the heater above the radiator until it bleads. Put the rubber cap back on.
Leave radiator cap off and let the car run two complete heat cycles.
While on it massage the hoses. Try to squeeze out every last bit of air. Top up.
Finally put back the radiator cap.

Often check the level at the expansion tank before you drive and refill if needed

No. Take rubber cap off, + rad caps. Jack front or park on hill so front elevated. Fill through rad until pipe under seat overflows. Replace that sprung (FRC74) cap. Keep filling til rad overflows. Fit rad cap & rubber cap. Run till fan kicks in twice. Allow to cool, then top up at rad cap & expansion bottle to halfway if necessary.

I have, in the past, run the engine for a while before replacing sprung cap under seat in the belief (hope?) that it would get any air out, but not proven. If you run it with rad cap off it will never get up to pressure & just vomit water, like a kettle if you hold the switch down.

OK. I refilled mine doing the 1st 2 heat cycles with the front cap off. But i stick a little 300 x 20mm pipe up the radiator and a funnel on top.  It wont pressurize thats why you can massage the hose very nicely. It wont vomit because of the pipe and funnel can buffer it.
Actually after 2-4 open rad cycles i put the cap on and never took it off again for a very long time. just refilled at expansion tank every 1000km. But then once i took a peek and it was still no air under the cap.

Ihave done more than 25.000 km without issues. Then i had the fan not coming on but luckily she didnt overheat. i realized the little screw at the bottom of the rad was leaking. Put in new gasket. Refilled again with the "open rad massage method" and didnt have problems again since then.

Might have been luck of course.... the leaking rad screw incident maybe makes it hard to judge.

That evil screw on the rad is so easy to access. Maybe some jealous ape driver undid mine on purpose.

Sometimes I wonder why myself and Raggy and Highly Jetted take the time to write articles and post pictures about this subject then a Pillock like you comes along who hasn't really got a clue how to pressure bleed a Hi-Jet Cooling system in five minutes or less, using just a watering can, a length of hose and some electrical tape .

Idiots like you make it so unnecessarily difficult for new members to grasp the subject and put them off owning a Hi-Jet. READ THE RUDDY ARTICLES THAT THAT HAVE BEEN PUT THERE FOR EVERYONE'S BENEFIT ( except for you it seems) instead of coming up with all this stupid rubbish about massaging the pipes and taking the radiator out etc. The only thing that needs massaging is your brain - if it is findable.

Okay lots of great info here. Thanks guys . I had a go yesterday but clearly did it wrong. Didnt do the heater matrix bit.

Also I never managed to observ no fan cycle. How long should I expect to wait for this?

I disconnected pipes to rad and poured water through.. this water came out as clear as it went in. Reconected everything. Filled coolant through front rad via funnel and 12 inch pipe fit for purpose. Did this till coolant overflowed from passenger side. Capped passenger side. Fired her up and continued to fill through the front then capped. Did this several times until post inspection peeks under the caps showed she was full.

Took her for a drive and stopped at our destination about 5 miles away and although the temp guage was only slightly right of the mid point, sounds of boiling and gurgling could be heard from beneith the passenger seat... Also some kind of steam coming from under the drivers side rear sliding door area. Had a look under there but couldn't really see where or what exactly was causing it. We Were in an open spot so I thought Maybe it was just the wind carrying it there from under the seat where the boiling noise was coming from. Drove her home after half hour or so, no o er heat. Then a bit later I drove around a bit more and she got really hot with a temp reading of a couple of notches short of the fully overheated mark. No noises or steam though. Just a bit worrying.

Going to empty her again today and try again. This time hopefully I'll get it right!

Okay so although my drive is a bit of a slope I think maybe i should Jack the front end. As you can probably tell I'm a complete newbie. Is it safe to Jack from the centre of the bar below the front bumper? Thanks.

The only way you can bleed the system properly is to get the air out of the Heater Matrix. All this rubbish about running the engine up and allowing two cycles. If you want that then go and buy A couple of bikes.

This bleeding is a very simple job done COLD. NOT HOT.
Above the radiator (993cc) is a small rubber cap with a tiny clip. Take this off and it will allow air and ultimately water to expunge from the Heater Matrix which is the cause of your lack of heat from the heater and making the air in the system expand and push the water out into the expansion bottle. Follow the procedure of topping up the system up to the point of the radiator starting to overflow.

THEN YOU NEED A WATERING CAN WITH A COOLANT MIXTURE WITH A 12 " LENGTH PIPE TAPED TO THE SPOUT.
A FUNNEL IS USELESS.
YOU CANNOT GET ENOUGH PRESSURE BEHIND THE WATER GOING INTO THE RADIATOR. ON THE END OF THE PIPE WRAP ELECTRICAL TAPE TO FORM A COLLAR WHICH FITS SNUGLY IN THE RADIATOR FILLER NECK SO THAT WATER CANNOT ESCAPE AND IS THEN FORCED UP INTO THE HEATER MATRIX. AIR BUBBLES WILL COME OUT FIRST AND THEN AIR FREE COOLANT MIX. WHEN THAT HAPPENS, PUT THE TINY RUBBER CAP BACK ON THE SMALL PIPE STUB. HAVE THE RADIATOR CAP READY IN YOUR HAND TO PUT STRAIGHT ON AND PULL THE PIPE OUT AND PUT THE CAP BACK ON. - - - - JOB DONE. IN 5 MINUTES OR LESS.

I sent Raggy some pictures of the radiator and pipe with the yellow Electrical tape around it and he did an article about. So have a hunt back through Raggy's posts and you can see from the pictures what I am talking about.

Best of luck Al, although if you follow these instructions you won't need any. It's just common sense and very easy to do.

Oh for crying out loud. You would have to stand your van on its tailgate to achieve that. Jacking it up is not going to get air out of the heater MATRIX. THE TOP OF THE MATRIX IS 4" ABOVE THE TOP OF THE RADIATOR. IT HAS GOT TO BE DONE UNDER WATER PRESSURE.

I have been on this Forum since 2nd of February 2013 and have put 2,903 posts on here since then and I have owned HUNDREDS of Hi-Jets since 2003, and I have probably dismantled or repaired more than anyone else in the country.

Highly Jetted is THE ORACLE OF KNOWLEDGE ON Hi-Jet's
but even he does not come close to the time I have spent with Hi-Jets. If you want to listen to someone who has just popped his head up again next here and has only 2.5 posts per month, 60 in two years to his name, then carry on.

By the way Al. Please don't think it is you that I am having a go at. Everyone has to start learning a new subject at the beginning. Every thing I have learnt (except humility - still working on that one - and it ain't going to happen) I have learned by getting out there and starting from scratch on my own. I have have asked for advice along the way but have always taken things to bits and put them back together again. Welding, Plumbing, Woodworking, Mechanics, Electrics all by trial and error.

The only thing I have had going for me is a sharp inquisitive mind. In the early 80s my wife and I went to the mainland and took a MENSA Test. She had an IQ of 161 and I of 159. Dratt!! I hate to be beaten.
Dread to think of what it is now after two strokes and getting old hasn't helped RETAIN the knowledge but there is still a lot of information in there still. Just finding it is the problem.
Right, now where the hell have I put my car keys 2 minutes ago??

Well theres one thing, with Woodie theres never a dull moment on here!

Thanks woodie. I really appreciate the help. I did as you advised and yes coolant mix came gushing from the heater bleed plug air bubble free from the pressure of the little set up. It was quite fun and thought I'd take a pic to share.



After this I turned her on and noticed very faint smoke coming every now and then from where I think the spark plugs go into the engine. I'm not sure if it came from there and even if I'm describing the place properly so I took a photo and marked the suspect location.

Any ideas what this could indicate? Thanks.

Well done Ala-Kazam. Ingenious. It is very satisfying to hear those bubbles coming out of the Matrix bleeder pipe and then the sound of the Coolant squirting out.

Then you know that you have done a "Proppa Jarb" as the locals say down here. Don't ask. Really weird lot down here.
The smoke you are seeing is from the crankcase vent. Any gasses that gets past the pistons builds up inside the engine and is vented back into the inlet system to be re-burnt. I expect that the rubber pipe has got hardened with age and heat. Put a new jubilee clip on it and if necessary cut the end off the pipe where the old clip was pushed onto the Alloy casting again with the new jubilee clip.

By the way, your spark plugs are to the right of the picture out of sight in your picture above the exhaust. And don't worry too much  if you can't find the fourth spark plug and lead.

That's what we like...photos! Saves a lot of description and misunderstanding. Looks a tidy little van from what we can see there. Well done so far and keep us updated.

Drove it around today, all was okay, I noticed a definite improvement. got to the same location i did the night before but this time with out the steam and gurgling. still warm under the passenger seat but nothing that looked too out of the ordinary. drove another 5 miles or so got into a shopping centre type place trawling through a big car park with a 5mph limit i saw the needle on the temp meter creep up to within mm's of the dreaded overheat mark. got a suitable parking spot and stopped. no crazy boiling noises or any steam/smoke though. went into the shop for about 10 mins or so and then drove her all the way home with no problems. pin staying within the first a quater of the meter.

I am thinking maybe the fan doesn't work... I dont know if its a noticeable thing... but I havent noticed it come on. I read on here about how people like to use their fan over ride when in slow moving traffic. There is a mystery switch on the right hand side below the fog light switches and rear demister switches, i posted a pic of it before and it doesnt seem to actually do anything when i flick it so i am wondering if it was the fan override switch and some where along the line its disconnected its self and taken the fans capacity to turn itself on with it. i dont know, my guess is as limited as my knowledge...

Could it be that all is now working correctly? The needle can climb up to that oh my God point as it has to heat up to a point where the thermostat will open and therefore the needle will drop back to its normal position which differs for most. After being stopped the needle will rise initially as the heat generated from the previous drive will have built up due to no water flow or air flow as being stationary but once started driving again the temp will fall to normal levels. Pull the unknown switch out and chase the cables to see what it or does not connect to then let us know with a few pics. Does it look as if any wires have been connected additionally to the temp sensor at the bottom of the radiator? That would indicate an override switch.
As a new hijet owner it can be nerve wracking watching the water temp (and I should know!) but at the moment you have bled it correctly so just enjoy driving it and see how things go. Just keep an eye on water and oil levels regular. I'll leave you with one good bit of advice Woodie gave me when I was in your position 'Stop being so neurotic about it!' never so much a true bit of advice given, enjoyed many miles of happy hijet driving since (I'm still neurotic but now the tablets help )

You definitely need to get a fan override switch working for sitting in traffic jams or crawling slowy. Until you can sort it out, two tips for you. First one as soon as you see stationary traffic up ahead put your heater on full blast and open nearside window a quarter and the drivers one fully open if it is not tipping it down with rain. Also open the sun roof if you have one.
With the heater on full blast it will drop the temperature by 5 to 6 degrees. Each time you are stationary, rev the engine up to about 1500 to 2000 rpm and will circulate the water round the system quicker and watch the temperature again drop some more.

Your temperature sensor is on the radiator at the bottom, on the 993's. There is a multilplug on it with three connectors. Only two wires are used. One in one out.
I can't remember if they are the live from the ignition or from the body earth. It is just like a light switch. It completes the circuit to the fan motor.
If you are not sure if the fan is working then run the engine up until the gauge is getting near to hot and you should hear the fan cut in for a short while and then go off again. As soon as it gets hot again it should cut in.
If it is not then it could be the Thermostatic switch or dirty contacts on the connector blocks on the fan itself or on the switch. So many variables that it is a question of trying various different possibilities. Try the engine running up to hot first and see if the fan is cutting in first of all. If not then come back on here.

This, as always, is so useful!

Based on what I read here, I realise I haven't bled the heater matrix. Went through the watering cane exercise, got coolant coming out of the rad caps, put the rad caps on and thought I was fairly heroic (based on my utter lack of mechanical ability).

Now I'm overheating and scratching my head. I'll try and identify the heater matrix and start again. One additional question, my fan doesn't currently come on by itself. I understand it could be the switch but presumably it could also be airlocked? Right now I think the thermostat isnt opening because although its overheating, the rad isn't getting hot at all.

I think I need to start again, right?

Woodie, you're a saint providing a valuable service; live long and prosper!

Hi Andy. It is pretty unlikely to be an airlock causing the Thermostatic Sensor not to work. It is situated under the passenger seat on the lower metal pipe. From underneath unclip the connector. It has two wires going into it although there is provision for 3.


Take the connector block off and pull it up gently so that you can get at the connector block. Using a length of wire put one end into the metal connection and the other end of the wire into the other terminal so you are bridging the connections. Turn the ignition on and your fan should start immediately. If it does then you know that the fan and its connector block on the body of the fan, and the Fan Relay next to the Water Filler Cap is also working. So that rules out three problems leaving the Thermostatic Sensor the suspect item. Give that a try and hopefully you can find the cause.

If not, get back on here again and I should have another Thermostatic Sensor.

Right, first of all take your grille off and you will see the little rubber pipe on the side of the Radiator Filler Neck. That is the bleed pipe from the Heater Matrix. Leave it in place.

Using the filling method I have described and Ala-Kazam has done so well to grasp. You must have filled the system from the filler cap and made sure that the water level in the metal pipe is full up and no more little bubbles coming up out of the engine and free of air. With just water coming out of the lower filler cap on the metal pipe put the cap back on.

Then continue to fill the radiator to overflowing. YOU MUST HAVE THE ELECTRICAL TAPE WRAPPED AROUND THE PIPE TO MAKE A SHOULDER. Push it into the neck of Radiator Filler neck making a nice tight fit. Lift the watering can up to above bottom of the windscreen level. You will hear and see the bubbles exiting into the filler neck from the little rubber pipe. Once it is running completely clear of bubbles put the radiator cap back on. Job done.
Run the engine up and feel the two rubber pipes on the Radiator. The nearside one should be getting hot. If both pipes are cold and your temperature gauge is right up high then it is the Thermostat that is suspect.

If you have to replace it you will ideally need a 1/4" drive socket set with long extensions . The set bolts are 6mm with 10mm head. If any one of them doesn't want to come undone for goodness sake don't force it. I use a long half inch drive extension bar as a drift on the head of the set bolt and give it a few hard taps with a hammer to shock it loose . Don't let the drift slip or hit the Thermostat Elbow or you are into more money to me for a thermostat elbow - not that I mind taking anyone's money. Although breaking the Housing is ultimately better than snapping one or more of the 3 10mm bolts.

Persevere with the 10mm bolts and get them out. What ever you do DON'T SNAP any of the three or you have got really big troubles on your hands.

OK, I'll start with the easy bit...but just for clarification, when you say leave the bleed pipe in place, do you mean don't disconnect it or anything at all? If I don't touch it, how does it do the bleeding?

Mine doesn't have a cap on it. It comes out the right hand side of the filler neck, does a U-turn, goes through another outer sheeth, and then heads up under the dashboard...

You don't need to do anything with it Andy other than watch the air bubbles coming out first and then the Coolant which will be hitting the filler pipe from the watering can. Once it is just Coolant and no bubbles remove the filler pipe and quickly replace the Radiator Cap. Can't answer any more questions today as I will be off out soon and not back until around 10pm.