Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Invicta]

Hello Birtys,

My temp gauge has been showing a range of temperatures recently so this being a Bank Holiday
I decided to investigate.

First thing I did was crack the top housing while getting the old Thermostat out.
Second thing was to panic (what with the Jeep being as rare as hens Teeth).
Then I spoke to the other J26 owner - Steve of Owens Exports in the States.
he recommended a housing for a Starion
I found one at Twigworth Breakers about 10 miles away.
I then bought a thermostat for a Mk 1 Shogun - it works at 88 degrees C so should show
as medium temp on my gauge.

After I fitted it all back together and topped up the rad I ran the engine
until the Thermostat did it's job at around medium on the gauge.

I then went for a test run at around 40 / 45 Mph.
At about the 2 mile mark the temp needle started to climb and stayed at hot/very hot
until I got back.

The top hose and top of the rad are hot but the rest of the rad down throuhg the cores and into the
bottom hose is barely warm!

last year I ran it with the innards of a thermostat taken out which made it stay just around cold.
The switched to one with the innards over winter to keep warm.
This summer I thought I'd try and fix the problem.

Any thoughts and suggestions will be very much appreciated as I use my truck for my gardening business.

Kind regards,

Bern
Tewkesbury

[Mike Pavelin]

Take the water pump out and see if it's got any blades left.

[PtP]

Could it be that you might have an airlock?

[Dave69]

you have probably worked out there is very little water flow through the system with such a temperature drop through the radiator.

you could check what Mike suggests or remove the thermostat completly and take the jeep for a run, after 10 mins you should be able to feel a temperature difference across the radiator mainly being the same temp. and later hot at the top hose and slightly cooler at the bottom.

what might happening is the thermostat isnt working correctly

[Invicta]

Mike, Dave, Ptp,

Thanks for such quick replies.

I had the water pump rebuilt 2 years ago so it's worth checking.

I did try and make sure there wasn't any air locks but again it's worth checking.
What's the recommended way to try and get rid of it if there is one please?

I'll take the thermostat out and see what happens then report back.

Guess what I'll be doing this Bank Holiday!

Bern

[Bubba]

you can see the flow simply by draining the rad enough to se the flow in the header tank i did once have a problem with a jeep and i found after a long search inc head gasket that it was down to the bottom hose sucking in on it self at round 2000rpm then over heating the engine   also could it be a poor conecton on your heater sender if its a leky one did the engine smell hot ?

[Invicta]

Bubba,

Thanks for the advice.
Ah the surfistikation of a header tank  
(I only have a radiator).

The idea about the bottom hose is one I hadn't thought of. I'll replace it
as the cloth outer is looking a bit frayed just in case.

Cheers,

Bern

[Bubba]

the top bit of the rad is what i meant as acts like a holding tank as the water filters in to the cooling cores

[Dave69]

as for vehicles without a header tank, the radiator filler should be the highest point in the cooling circuit so any air should collect and vent off at this point. what you could do is run the engine with the radiator cap removed until the engine reaches operating temperature (hot). during this processyou will loose water as it gets pushed out by the air but as the level drops slightly add more water. when the temp has stabilised and your getting no more water being pushed out then switch off the engine and allow to cool. remember the water level will then drop and the water cools so top up when needed. the water level drop shouldn't great an air lock in the radiator but when you fill do it slowly as to allow any air to escape as you fill. if there is any air trapped it shouldn't create the symptoms like before.

As Bubba says check the bottom hose first for structual integrity. If the hose is stright then replace it for something more substancial (sp). if your seing something that fraying on the outside of the hose that might be a the mesh covering that is somethimes slipped over the top to prevent bulging of the pipe and additonal wear from rubbing

[Invicta]

Bubba, Dave,

Once again thanks for your advice on this.

I followed your tips, especially the filling slowly which did result in a few air bubbles being released.

The main change I have made is to use the adjustment screw in the top of the thermostat itself.
By turning it the spring/plunger mechanism is opened/closed. After 5 trials I've found the ballance
between keeping the engine at a medium heat while also allowing enough heat to be generated
to warm the cab when the heater is on.
I took it for a run around The Malverns and on to the Upton Upon Severn Folk Festival and all seems to be working fine.
Water is circulating and Thermostat working.

I'll run it this week and post back with the results.

Incidentally the TOR Photoshoot had to be postponed due to heavy rain so if there are any club stickers still available I'll happily put one my little truck ready for the next session.

Many thanks for your help with this.
Now I'm ready to go gardening, and earn some money, again tomorrow.

Cheers chaps,
Bern

[Dave69]

Bubba, Dave,


The main change I have made is to use the adjustment screw in the top of the thermostat itself.
By turning it the spring/plunger mechanism is opened/closed. After 5 trials I've found the ballance
between keeping the engine at a medium heat while also allowing enough heat to be generated
to warm the cab when the heater is on.

that's a new one on me, a flow regulator in an old car by using an adjustable thermostat

[Invicta]

Dave,

I can't take any technical credit for this. It was pure luck.
I took the alloy housing off a Mk 1 Shogun in a local scrap yard. Wiped the accumulated anti freeze
crystals off the thermostat and thought "This might come in handy"!

The adjusting screw was set in position. During manufacture the copper body had been pinched to stop
the screw turning. A bit of work with my pliers and it's now become adjustable.
A couple of turns down for the summer and a couple back for the winter will hopefully do the job.

I'll keep you posted.

Bern

[Dave69]

sounds like when the screw has been loosened it has allowed the thermostat to move slightly off it's seating thus allowing the water to flow freely past, and with adjustment create a stable flow when warm. still might be a case to source a proper thermostat/cap at some point but at this time you have fashioned a working system.