Overheating

[catchawave]

Hi all,

I am running a t25 with an EJ20 2.0 non turbo subaru fitted.

A quick queston, My van still overheats on short runs and tootling round town.

After getting it up to temp (around 90C 190F ) the pipe from the Thermostat is cold. I am going to change the thermostat anyway as I didnt do it when I fited the engine.

Should this pipe be hot and also it doesnt feel like it has much water in, so Airlocks Maybe?

Should the expansion bottle be full or half full ( the one with the pressure cap on).

Happy Dayz.
Andy

[Frank_Andersen]

What pipe do you call "from the thermostat" ?
The 5/8 (16mm) pipe is the return from the heater. It is fed from the heater and the 5/16 (8mm) hose to/from the trottle housing. If these are blocked in any way the thermostat will not open. This is the hot water that makes the thermostat work.
Is your heater working ?

I run a 2.5DOHC in a speedster replica and using a VW Polo expansiontank. The 8mm pipe on that tank is only 3mm inside. I opened that up to 5mm and it lowered the temp. 5-10 degrease.

[catchawave]

Hi.
Yeh heater is hot. The pipe I mean is the large bore leaving the thermostat housing going to the rad up front. I think you a right it does come from the rad and is a return pipe.
No problem with the pipes running to the heater. They are hot.

Also the hot water is pumping into the header tank. Not sure how full this actually should be.

Andy.

[Frank_Andersen]

OK. Yes the large lower pipe is the return from the radiator.
If the small pipes to the pump and thermostat are hot then you have to make sure the thermostat opens. Have you tried to run without a thermostat ? Just to see if the plumping works ?
Then you have to make sure that ALL of the radiator is hot. If not it has airlocked or is blocked from dirt inside. And the large return should also be hot.
The headertank full or not ? Mine from the Polo is not full, just up to the mark.
But I see on the internet that people running a T2 tank, the tank is full but they have an ekstra fillertank also ?

[catchawave]

I ran up my engine and then took it for a short run. after this the rad was starting to get warm but the large hose that connects to the thermostat housing wanst warm.

I will check next time I take it for a run.

My header tank is just above the halfway mark which say MIN. Its a t25 tank.

I am a little confused as to where any air could be trapped.

Andy

[Griff71]

Catchawave, if you are running a T3/25 header tank it should be full to the top. The filler tank should also be on max and check this regular. The system works under pressure and essentially draws coolant from the filler tank into the system and back out when needed. The cap works as a valve.

So if your header tank is not full but your filler tank is i would suggest you have a faulty header cap or connecting hose. Also bear in mind pressurised coolant has a lot higher boiling point so if your system is unable to pressurise through a leak or faulty cap you will see the symptoms you are experiencing.

Failing the above i would suggest a block test just to check the headgaskets are not problematic. Not sure about 2.0 but 2.5's are a nightmare for failures have had to do head gaskets twice in 4 years and a 3rd is on the cards this month.
_________________
89 Crew Cab (Subaru 2.5na)
71 Drag Bug (1955cc dual 40s)
65 Ragtop Bug (low & stock)

[catchawave]

Thanks dude,
My header is half full, I will top it right up tomorrow and keep an eye.

Cheers for the info.
Andy

[catchawave]

Hi all,

Just an update, seems I am losing water from header tank/ cap,

Ordered new tank and cap, see what happens.

Like you say, if it wont hold pressure, it will get hot.

Cheers.
Andy