So how hot is normal?


When I bought my hi-jet the previous owner reassured me that I'd have no trouble with overheating, he also assured me that replacing a head gasket was a two hour job.

So I've been having great fun nipping around town and was quite happy that the temperature gauge wasn't up at the high end. But last night I took it on a 'proper' run of about fifty miles and the gauge was still pointing at rock bottom.

Is this normal, or should I look into replacing the gauge?

temp guage-hijet

First of all mate, check all your levels. Thats both radiator caps and the oil level, if they are all ok then it could be simply that the temperature switch is faulty or the connector wire is loose. Check the wire first to see that its connected properly to the switch. It could however be a faulty or sticking thermostat. Not a hard job but if your not mechanically minded then its a garage job im afraid. I'd suggest you take it to a main dealer, reason being they have the correct parts required and my van has just had both the radiator caps done along with the modified fan switch and thermostat fitted to prevent overheating. My temp guage now sits comfortably in the middle of the scale and is quite quick to get there from cold which indicates all is now working ok.

The previous owner to myself had all this done about 3 weeks ago prior to me buying it along with new spark plugs. Ive since changed the oil and filter and airfilter and fuel filter to complete the full service. Ive also added slick 50 oil treatment to the engine and slick 50 fuel treatment to the petrol tank. It now runs like a dream. Does your heater work ok???? check this also. If not then you could have a blocked matrix or an air lock. My suspicions are if all the above are ok is a minor problem with the switch or sticky/US thermostat.

If the head gasket had gone you would be loosing coolant blowing smoke and loss of power when driving it. Hope this helps.

Regards. Brendan.


the heaters are working fine, I will check the levels though, I'm still so green to this van that I don't know where the caps are! Is one of caps in the dashboard next to the speedo?

When the workshop manual arrives on CD I should be alright for more basic repairs, we used to keep an old Series III Land Rover on the road!

Sadly I've experienced head gasket failure before, it was the death of my Chevette, and it was only going to cost £35 to repair!

I make badges!

I make gibberish!

Hot Hi Jet.

2003 Sirion SL 1300. And I love it.
Don't like the new shape much.

Not had much dealings with the Hi Jet.

Didn't you find it strange that the previous owner mentioned overheating? I would have been on my guard straight away.

Most guages sit slap in the middle between hot and cold and are designed to do so.
Check wiring. Could be sender or the actual guage.

If the engine was actually overheating I beleive you would have blown the gasket by now.
Advice from others is well said.

Good Luck.


2003 Sirion Rally 4. And I love it.
Don't like the new shape Sirion much.Sorry.

Hot Hi Jet.

2003 Sirion SL 1300. And I love it.
Don't like the new shape much.

Well you learn something everyday !!

Most unusual for Daihatsu.


2003 Sirion Rally 4. And I love it.
Don't like the new shape Sirion much.Sorry.

Hot Hijet

Quite a common problem and usually caused by either of the rad cap seals knackered or the electric fan switch not working.

To check opressurisation warm her up and the hoses beneath the passenger seat should become firm.

The Elactric fan switch is on the passenger side of the vehicle's radiator. I sprayed mine with WD40 and replaced the cap beneath the seat and all was well. I have since sold the van and the new owner, now two years, says it never overheats.

Whilst these are badged Daihatsu they are made by Piaggio in italy,Piaggio Porter, Not sure whether the engines are but expect rust in the bosy and it is worth checking the seams beneath as rust starts early on. Mine was a 200 and 3 years old when I got it and all the seams had surface rust on their leading edge, being Silver it was easy to see.

Good Luck



I had problems with my van overheating, mainly due to a blocked radiator. The previous owner removed the thermostat to try and keep it cool. I've replaced the radiator with a re-conditioned one (£85), added a product called K-Seal ( made by Kalimex) to the cooling system. This is GUARANTEED to cure minor cooling system faults, including slight cylinder head gasket leakage. Take off both radiator caps ( The one on the radiator does not have the spring on it, just a rubber seal - make sure that this is in good condition ). Fill the cooling system from the radiator until the water comes out from the filler on top of the engine, then replace that cap and continue filling the radiator until full. My van's temperature gauge never rises above cold now unless I'm in standing traffic, when it rises to the halfway mark and the fan cuts in. If it had a thermostat in, I think it would overheat still in standing traffic, so I prefer it to run cold. I don't use the van much, so any increase in fuel consumption doesn't really bother me. Any further advice you need, just ask.

Hijet overheating

Hello again mate, 1 of the radiator caps is under the passenger seat and the other ( main one to check regulary) is behind the front grill. A small flat tip screwdriver will help you to ease the cover open. Its hinged and pulls off once tilted ( Be gentle with it as its plastic) 2nd radiator cap is behind it. Please be careful when undoing from hot. Best to do it cold mate to be safe.

Regards. brendan.

Hijet overheating

Sorry mate, forgor to mention, the coolant expansion bottle is also under the passenger seat adjacent to the radiator cap. Its the plastic bottle with the pipe running into it. The level should be between the low and high level. Ive made mine more to the high level tho to be sure. The other small plastic bottle with the small cap is your windscreen washer bottle. Try not to get them mixed up with the antifreeze my friend.

Regards. Brendan

doh again!

I'm not doing too well with the hi-jet DIY today, I found the caps ok and put in a bit of coolant but my radiator panel wasn't hinged or plastic, it is metal and some bugger had GLUED it on! So now my poor hi-jet is out in the street with his privates exposed!

I've put some photos on my blog, and it's all looking a bit sad Sad

I make badges!

I make gibberish!


Has it got thermostat? I am not familiar with hijet. Thermostat probably stuck fully open. Alternatively has someone removed the thermostat rather than fitting a replacment?
Any engine not reaching working temperature will drink fuel.

Hi Jet air lock 'vent'?

Can anyone tell me where the 'vent' on top of the Hi Jet engine is? I guess this is to get rid of air locks, when refilling the cooling system, my Hi Jet's overheating.