Cooling system

[Hooligan]

If your not convinced about dumping cold water from a freshly opened Stat into a hot engine do a quick search on MGF's/Landrovers and the Rover K series engine. Some engine cooling systems are very badly designed, and this cold water flow problem can warp heads over time CAUSING premature head gasket failure. Remedy with these engines (Other than fit a remote Stat) is to drill 2x 6mm holes in the Stat to allow a constant small coolant flow.

[Aethelric]

With the stat in the normal position, and assuming that Haydn is right about the flow, is this what happens?

a. Thermostat is closed bottom hose is filled with cold water.

b. head heats up, transfers heat to thermostat, thermostat opens.

c. a small amount of very cold water flows over the thermostat cools it down and shuts it off. Minimal effect on the head. Some warm water from the radiator enters the bottom hose.

Go back to b. until there is sufficient warm water in the bottom hose to keep the thermostat stable and cool the head.

The delay in opening the thermostat caused by the cold water in the bottom hose could cause the head to overheat. Did I see a post somewhere about drilling a small hole in the thermostat to arrange a bypass? That would allow a little flow through the bottom hose enabling it to warm up.

Dave

[The Great Pretender]

If your not convinced about dumping cold water from a freshly opened Stat into a hot engine do a quick search on MGF's/Landrovers and the Rover K series engine. Some engine cooling systems are very badly designed, and this cold water flow problem can warp heads over time CAUSING premature head gasket failure. Remedy with these engines (Other than fit a remote Stat) is to drill 2x 6mm holes in the Stat to allow a constant small coolant flow.

That was covered earlier in this thread.

[The Great Pretender]

Dave, that was covered earlier too.

Even with the stat removed from the inlet and with the rad hot from top to bottom the bottom hose was still cold suggesting the coolant was flowing through the degassing tank. Strange and why?
Why not check your bottom hose after a run?

[haydn callow]

Hooligan... you will find this http://www.mgfmavhh.ukf.net/ on page 3 of this topic.....

[haydn callow]

Looking at the link above..the MG engine would appear to have it's coolant flowing in the opposite direction to the Bongo...ie..Hot coolant from the engine leaves via the Bottom hose and cool coolant enters the engine via the top hose.

[Aethelric]

Dave, that was covered earlier too.

Even with the stat removed from the inlet and with the rad hot from top to bottom the bottom hose was still cold suggesting the coolant was flowing through the degassing tank. Strange and why?
Why not check your bottom hose after a run?

Well... Bigdaddycain reported earlier in the thread that with the stat removed the bottom hose got hot and the engine took a long time to warm up. Now that seems logical to me, unless there is blockage somewhere in the head/stat/bottomhose/radiator path.

My earlier post, which assumed that the coolant flows out of the head into the radiator gave a reason for the flow through the degassing or header tank. There seems to be at least three pipes leading to the radiator. How do we KNOW which way the coolant is supposed to flow through each of them?
Dave

[The Great Pretender]

Dave, that was covered earlier too.

Even with the stat removed from the inlet and with the rad hot from top to bottom the bottom hose was still cold suggesting the coolant was flowing through the degassing tank. Strange and why?
Why not check your bottom hose after a run?

Well... Bigdaddycain reported earlier in the thread that with the stat removed the bottom hose got hot and the engine took a long time to warm up. Now that seems logical to me, unless there is blockage somewhere in the head/stat/bottomhose/radiator path.

My earlier post, which assumed that the coolant flows out of the head into the radiator gave a reason for the flow through the degassing or header tank. There seems to be at least three pipes leading to the radiator. How do we KNOW which way the coolant is supposed to flow through each of them?
Dave

Why do you think I can give you answers when im still asking questions?

[haydn callow]

A year ago there was the epic 20 odd page topic on this very subject.
Because I had misunderstood somthing I had been shown/told. I put forward (strongly) the idea that the coolant flowed round the Bongo in the opposit direction to what everybody thought. i.e. from the engine via the biottom hose into bottom of rad, up rad and back to engine via top hose. I gave the reason that the bottom hose was always cool as the stat is hardly ever open and the bypass flow could deal witn normal cooling needs. After much debate It was pointed out that this was NOT the case and I rejoined the mainstream thoughts on the matter.

[The Great Pretender]

Dandy should be back soon so it will be good if he and Haydn could do more tests on pressure out of the head. Im shure this is where premature problems come from.

[haydn callow]

A couple of photos of the in line stat housing I managed to make up from parts foud on ebay.

[The Great Pretender]

Very pretty H C where are you going to fit it?

[The Great Pretender]

Dave, that was covered earlier too.

Even with the stat removed from the inlet and with the rad hot from top to bottom the bottom hose was still cold suggesting the coolant was flowing through the degassing tank. Strange and why?
Why not check your bottom hose after a run?

Well... Bigdaddycain reported earlier in the thread that with the stat removed the bottom hose got hot and the engine took a long time to warm up. Now that seems logical to me, unless there is blockage somewhere in the head/stat/bottomhose/radiator path.

My earlier post, which assumed that the coolant flows out of the head into the radiator gave a reason for the flow through the degassing or header tank. There seems to be at least three pipes leading to the radiator. How do we KNOW which way the coolant is supposed to flow through each of them?
Dave

So? Have you felt your bottom bit latley?

[Aethelric]

Dave, that was covered earlier too.

Even with the stat removed from the inlet and with the rad hot from top to bottom the bottom hose was still cold suggesting the coolant was flowing through the degassing tank. Strange and why?
Why not check your bottom hose after a run?

Well... Bigdaddycain reported earlier in the thread that with the stat removed the bottom hose got hot and the engine took a long time to warm up. Now that seems logical to me, unless there is blockage somewhere in the head/stat/bottomhose/radiator path.

My earlier post, which assumed that the coolant flows out of the head into the radiator gave a reason for the flow through the degassing or header tank. There seems to be at least three pipes leading to the radiator. How do we KNOW which way the coolant is supposed to flow through each of them?
Dave

So? Have you felt your bottom bit latley?

I finally got to doing something which may be a useful piece if data.
I fixed the probe of an electronic thermometer to the bottom hose, about 6inches below where it goes into the engine, threaded the wire through to the cab and kept an eye on it when I went for a run. It was a cold day (around 10C). Under normal running about town the temperature seems to stay between about 28C and 35C. When stationary with the engine running (not something I usually do, but thats another thread) the temperature creeps up to about 40C. When travelling at around 75mph up and down hills it can go as high as 45C. I did about 100 miles and it did seem to be working as I would have expected - no surges of temperature, just steady changes up and down.

The probe is taped onto the outside of the pipe with self amalgating tape so these temperatures will be lower than the coolant inside. I think most folk would class a surface temperature of 28-35 as warm and 45C as hot.

The thermometer is still there. I'll keep an eye on it.

Dave

[lizard]

All this seems about average from what I have read on this subject. Normal running, temp is normal (are all Bongos running at same temp?). Idling, temp rises and stabilises. With high speed and uphill running, temp can rise even higher. Can normal running Bongos suddenly develop problems (design/manufactoring fault, not breakdown because of age) and overheat without any previous problems.