Revs rising and falling..

Hey there, my names Sebastian.
I'm in a bit of a pickle..
Yesterday I caught the train down to Hampshire to go and have a look at a 1.3 hijet. It is in pretty good shape, test drove it for half an hour, everything fine apart from manual radiator switch had been put in (after reading articles on your website- uh oh!) Ended up buying it for £700 and drove it back to bristol. Everything went smoothly until arriving at the outskirts of the city. The temp gage had been sat on cold for the whole journy and so i hadent turned the fan on. Suddenly the needle rises, slight smell of hot engine and then the engine fault light comes up on the dash. I pull over and stop the engine. Twist off the water cap and release lots of steam. Wait for half hour and start it up again. Warning light is off. I drove another 10/15 mins and the temp is all the way up again. Bubbling water.
Stop again. Had a couple of hours kip in the back until the engine had cooled right down. Started it up again with the fan running and drove it back home. Parked up and it felt like it was right about to blow. Bubbling water and when idling the revs rise and fall every second. Left it over night and went to try it today and the same thing- revs rise and fall, in first gear jerks forward stops, jerks, stops and so on but in second drives fine.. and overheats after 10 minutes drive.
After looking at the daihatsu hijet owners site which I must say is an absolute godsend! I'm happy trying to solve the overheating, just the revs I have no idea about..? Couldn't be the carb could it..?

Dont worry about the revs, that happens when you run out of water, its controlled by water temp. Concentrate the worrying about the head gasket, cos it looks like it needed one. Which is a regular reason for someone selling a Hijet....
Make sure you are following the filling instructions to the letter. It may just be airlocked. A small.leak will do that over a long journey. But you need to be sure. F+cked head is a possibility if you boil it sore enough.

Thank you!! I was so worried bout that.. Do you know the filling instructions..? I've got a big bottle of coolant..

One more thing. The interior heater is only blowing out cold air.. Does this point to a particular solution.
Also with the coolant, do you fill the radiator cap right up to the top..? Because at the moment opening the cap you can't see anything inside..
Thanks again.

To bring this together - thanks for the message via facebook!

Hey there, my names Sebastian.
I hope you dont mind me sending you this message but im in a bit of a pickle and you really seem like you know what your talking about..
Yesterday I caught the train down to Hampshire to go and have a look at a 1.3 hijet. It is in pretty good shape, test drove it for half an hour, everything fine apart from manual radiator switch had been put in (after reading articles on your website- uh oh!) Ended up buying it for £700 and drove it back to bristol. Everything went smoothly until arriving at the outskirts of the city. The temp gage had been sat on cold for the whole journy and so i hadent turned the fan on. Suddenly the needle rises, slight smell of hot engine and then the engine fault light comes up on the dash. I pull over and stop the engine. Twist off the water cap and release lots of steam. Wait for half hour and start it up again. Warning light is off. I drove another 10/15 mins and the temp is all the way up again. Bubbling water.
Stop again. Had a couple of hours kip in the back until the engine had cooled right down. Started it up again with the fan running and drove it back home. Parked up and it felt like it was right about to blow. Bubbling water and when idling the revs rise and fall every second. Left it over night and went to try it today and the same thing- revs rise and fall, in first gear jerks forward stops, jerks, stops and so on but in second drives fine.. and overheats after 10 minutes drive.
After looking at your website which I must say is an absolute godsend! I'm happy trying to solve the overheating, just the revs I have no idea about..? Couldn't be the carb could it..?
Thanks again!
Seb.

So I replied

Hi Seb,

Sounds like you've bought one with known troubles, which is very common. People often turn up on the forum after buying one that over heats on the drive home.

The rev's going up and down is caused by a lack of coolant in the idle control valve at the top of the inlet, but don't worry about it at all, because as soon as you cure the over heating problems then that will sort it's self out. It doesn't have a carb as its got electronic fuel injection.

The temp gauge problem is your first issue, if the gauge does work and it sounds like it does, then it wasn't working because there was no water in the cylinder head round the sensor itself. Driving it like that is a pretty sure fire way of blowing the head gasket I'm sorry to say, but you weren't to know. And it was probably already blown because it will have been over heated loads of times already, thus why it has been bodged about with a fan switch by some idiot.

I think the person who sold it too you knew all about it's "problems".

What you need to do, if the van is worth it bodywork wise and rot wise, is take the head off, get it skimmed, put a new head gasket on it. Put a new thermostat on it, replace the rad caps, replace the water pump, inspect the radiator - put it all back together with new jubilee clips, give it a little pressure test using the method on my site - and if it holds air then fill it with coolant and you'll be good to go. Parts wise it will cost you about £100, plus about £40 to get the head skimmed and pressure tested and get them to set the tappets up while its there. Labour wise it'll take you about 4 hours to strip it down, another 2 hours to inspect and test everything, and another 4 hours to put it back together.

I'd seriously recomend joining the microvan owner forum, where you can read all about how a girl did her own head gasket job about 6 months ago, and we can talk you through it.

Don't take any short cuts or half jobs of the work, or you'll be right back to square one and it'll only cost you more money and time.

I can answer your questions all the way, and I can tell you where to buy all the parts from to save your self a fortune.

So got on the hijet forum, which it looks like you have Sebahdee!

All the best, Matt (highlyjetted)

The heater won't work when it's got no water in it, just like the idle control valve.

So really you need to read Daisy's story with her's... she wasted alot of time and effort before solving the problem, which she did a damn good job of, but I would recomend reading her story as it will save you so much time, effort and heart ache.

https://hijet.forumotion.com/t935-mechanics-that-are-good-with-hi-jets-the-answer-to-this-is-if-you-want-a-job-done-properly-do-it-yourself

https://hijet.forumotion.com/t1041-reasons-why-my-hijet-was-over-heating-1-2-3-4-and-more

I'm thinking a "So, You've Bought A Shit Hijet?" sticky may be in order?

I thought this was very tactful for me:-

Sounds like you've bought one with known troubles, which is very common.

But yes, It think your right about the sticky, but making the information concise is quite a tough task.

Yup, it's not too healthy!.. Someone's put boy racer wheels and wheel arches on, lengthened the axels and it had a ginormous mental exhaust spare in the back.. Should have read the signs and stayed away! I just got too excited!..
On the other hand though I'm quite excited about this little project. There's nothing better than taking something apart and learning about it..

So after reading your incredibly helpful reply HighlyJetted and doing lots more research I jumped on the train after work and thankfully found the van where I left it in the morning with no parking ticket or clamps!
Topped the cap under passenger seat with coolant and started the engine. No revving problems! Drove off, no temperature problems! Let it cool down. Topped it back up with coolant.
Next day coolant (ill call it water from now on) levels had fallen. Topped it up. Drives fine. Idling speed maybe quite high though..?
Next day, absolutely fine. Temp stays at pretty much cold, about 1 10th of the way up. (Seems pretty cold..?). Both pipes from radiator are warm. No hot air in cab though.
Give a lift to a friend to bus station, she got the time wrong, we saw what we though was her bus drive off. I followed it into the motorway.. Wrong bus!.. Driving about 70 for half hour, temp fine. Get back into the city and temp starts rising. I put the rad fan on. No help. Temp rises to hot and stays just in the middle of the block of paint on the far right of the temp gage. (right the way over..) check pipes coming from radiator.. Cold.
Let engine cool. Open the cap under passenger seat have to fill with plain water, no coolant left! Started with a 5 litre bottle haha!
Temp back to normal. Driving fine.
So in my opinion (which isn't very valuable as I know little about mechanics..) the thermostat is temperamental. Or what I would be more likely to think is that there is a leak, water getting out, air getting in. Causing an air lock (not quite sure what this is..) filling the cap with water fixes it until the next long hard drive when I guess water is pushed out and air sucked in harder..?
I checked some of the water pipes and they are pretty rusty!! Clips look passable but could do with a change. Noticed a brand new jubilee clip on one of the radiator pipes. What a bastard that sold it too me!
Anyway. Like what daisy said though, it's a love hate thing, I absolutely love the van to bits but these problems are so frustrating!
Ill take some photos and try to get them up on here today. Thank you so much again for helping me out! I can't wait until its happily pottering about..

wow, that all sounds familiar!
good luck with fixing it, and yes it is nice to take it apart and know whats going on in the engine, not particularly convenient when its your only vehicle.
i NEVER want to see the inside of one again tho!

Are you filling it from the radiator cap or the one under the seat?

The one under the seat.. For now.. I live on a boat so there's not much space for tools and socket sets so next time I've a few minutes with a set I was going to fill the radiator until it overflows the lower one. Then fill the rest up.. Let it hear up, cool down any top it up again..
Is there much point doing this until I find out if there is a leak..?

Socket sets? What for?

Don't you need to take the grill off to get at it..?

Yes. Theres 2 wee bits to put your fingers in under the top bit of the grille, pull towards you carefully and it will release from the top. You can then carefully remove it from.the bottom hinge if you want.