thermostat

[Sidb]

1995 2.5td
When checking my bongo ready for the winter I found there was no thermostat or antifreeze,
I changed rubber hoses,water pump put a genuine thermostat in bleed the system but was getting back pressure through header tank in the end the head went,
Put it in garage bought a complete cylinder head kit all fitted but still back pressure through header tank,runs great without thermostat I need help my van has been off the road for weeks now can I run it without thermostat.

[mikeonb4c]

1995 2.5td
When checking my bongo ready for the winter I found there was no thermostat or antifreeze,
I changed rubber hoses,water pump put a genuine thermostat in bleed the system but was getting back pressure through header tank in the end the head went,
Put it in garage bought a complete cylinder head kit all fitted but still back pressure through header tank,runs great without thermostat I need help my van has been off the road for weeks now can I run it without thermostat.

There's always some pressure in the system/header tank when engine up to temp but are you saying its excessive? What does the garage who fitted the new head have to say?

[Sidb]

Hi mikeonb4c

back pressure is very excessive
Garage says he just cannot work out why so he has left thermostat out hoping to pick bongo up friday

[g8dhe]

What do you mean by "back pressure" ?
The system is pressurised upto 1.1 bar above atmosphere when its working. That pressure will remain for quite some time until the engine has cooled right down.

[Bongolia]

Hi Sidb
Is the pressure there from cold start up? If yes does it pump back through the expansion bottle with the cap off?
Is the garage familiar with the bleed procedure?
Did he bleed it that way?
Is this the same garage that fitted the new head?
Did you supply them with the head?
Questions questions always questions
Oy vey already!!

[teenmal]

Is this just a new purchase or has the engine been operating without a thermostat for quite a while .
Did the garage change the radiator.

In These vehicles Its a nasty old trick to mask a overheating/pressure fault by taking the centre out of the thermostat.

[Bongolia]

Is this just a new purchase or has the engine been operating without a thermostat for quite a while .
Did the garage change the radiator.

In These vehicles Its a nasty old trick to mask a overheating/pressure fault by taking the centre out of the thermostat.

Tsk,Tsk,Tsk.

[teenmal]

Is this just a new purchase or has the engine been operating without a thermostat for quite a while .
Did the garage change the radiator.

In These vehicles Its a nasty old trick to mask a overheating/pressure fault by taking the centre out of the thermostat.

Forgot to mention the front heater matrix is worth checking for a good flow.

[Sidb]

Thanks all.
there was no Thermostat in bongo when I purchased in May 2016
New Radiator fitted 2016
End November I changed Hoses,Water Pump & Thermostat Bleed system, Heaters and temp gauge all worked fine took it for a run the coolant was gushing out off the header tank.
Stripped all down again flushed out the full system put back together bleed system let it run Thermostat opened let it run bit longer coolant started gushing out again with cap off,Done this a few times the same thing coolant gushing out header tank with cap on or off.
I bought a complete Mazda Bongo Cylinder Head Kit got that fitted but still have problem of coolant gushing out so I am running my Bongo without a Thermostat.

[teenmal]

Yes the front heater matrix is worth checking for a good flow and return.

[Bongolia]

I cannot understand why the garage that fitted the head couldn't get to the source of the problem.
Is there not a Bongo garage that you could take it to that may be quicker in the long run.
What sort of distances have you driven it without the stat fitted
With no stat what temperature does the engine reach on the temp gauge and do you have pressure in the top and bottom hoses when it has fully warmed up?
Do you have heat in the cab?

[Sidb]

I have now found a garage that works on Bongos so I will be taken it to get it sorted.
I am driving it every day to work and back with out thermostat it is only about 30 miles there and back.
The temp gauge does not move very little heat in cab.
I should have looked into things more before putting it into the garage to get head done You learn by your mistakes some times costly mistakes but with doing some phone calling I have found a guy in Newcastle that does all Bongo repairs around the north east he has agreed to sort out my problems for me.
Thanks every one for your reply will keep you up to date with my progress.

[rita]

When the garage/mechanic fitted a new head did he/she show you the fault with the Old head?

[Bongolia]

I have now found a garage that works on Bongos so I will be taken it to get it sorted.
I am driving it every day to work and back with out thermostat it is only about 30 miles there and back.
The temp gauge does not move very little heat in cab.
I should have looked into things more before putting it into the garage to get head done You learn by your mistakes some times costly mistakes but with doing some phone calling I have found a guy in Newcastle that does all Bongo repairs around the north east he has agreed to sort out my problems for me.
Thanks every one for your reply will keep you up to date with my progress.

Likely that the head is Ok based on what you say unless its a heat related crack.
On the 2.0lltr there is a directional valve in one of the hoses. Does anyone know of such a device on the WLT engine?
I have looked on lushprojects site and I cannot see one anybody out there know if there is?

[Bongolia]

Sidb. I am intrigued.
When you changed the hoses did you also change the two smaller hoses on the thermostat housing?
Without a workshop manual or images other than those on lush. I am wondering if the previous owner has crossed these over.
It may not be possible to do this.
Simplest way to find out is if anyone has got or can get an image of the housing with the hoses attached and where those hoses should be running to and from?