Is my water pump belt slipping?

richardpope50 · Post by **richardpope50** » Tue Sep 03, 2013 6:23 pm

Thought another view showing levels would be of interest.

unstable load · Post by **unstable load** » Wed Sep 04, 2013 5:26 am

There could be a few bubbles hiding in the 2 hoses going aft, too.

DEVONMAN · Post by **DEVONMAN** » Wed Sep 04, 2013 8:21 am

It would be benificial to source a different thermostat housing, one which exits straight out the front without a large kick up. As things are at the moment, any air that would normally find it's way to the top of the swirl pot is rising to the hump in the top hose making the swirl pot effectively useless. It might as well not be there at all. If you are unable to lower the hump in the top hose then connect a small bore connection from it's highest point to the small pipe at the top of the swirl pot. This will effectively extend the swirl pot volume to include the high point of the top hose.

Also it's worth checking again that the top tank of the rad is free of air.
(There's no way for air to get out of the top tank other than via the bleed screw)
As a permanent fix I would make a small bore connection between the rad bleed point and the pipe that runs between the swirlpot and the header tank. This assumes you have put a bleed in the top hose also.

mgbv8 · Post by **mgbv8** » Wed Sep 04, 2013 4:44 pm

I've got a forward facing stat housing. Saved loads of aggro with the top hose.

If that tank on the left is the expansion tank you could take a small line from the hump in the top hose and run it into that exp tank via a top connection with dip tube.

Or instead of a pipe how about fitting a small vent connection that could be used for cold top up at the high point.

I've had to do this with Jays Escort due to the lash up of pipes. His remote stat housing is the high point so we fill it via the top hose unti it runs out of the rad. Then hoses back on and take out a 1/4" bung and use a mineral water bottle with a 4mm hole drilled in the top so we can squirt a thin jet of water into the hole until full.

I've taken an expansion line to the tank lower in the system and as long as from cold the tank has a coulple of inches of water to cover the dip tube shes fine.

Lots of ways to skin this cat I guess.

richardpope50 · Post by **richardpope50** » Wed Sep 04, 2013 6:47 pm

Many thanks for the continuing suggestions. The bleed valve I've ordered is a typical ali pipe with a threaded hole for a sensor - many on eBay. It's going in the highest point of the top hose. If that does not work, I've still got options of taking a pipe off the sender hole to somewhere as well as a straight thermostat outlet

Due tomorrow - I hope.

unstable load · Post by **unstable load** » Thu Sep 05, 2013 8:48 am

If you can get a straight outlet and are able to rotate the swirl pot 90 degrees anticlockwise it will greatly shorten the hose run and minimise risk of bubbles. If you really want to get fancy, you could get the spigot to the swirl pot cut off and reattached so it's perpendicular or slightly downward facing because any residual air will collect at the top of the upward slant of the hose.
You will need a longer bottom hose, but that should be OK as long as it's routed so the air runs up to the swirl pot.
Then, you will need to address the hoses running aft and probably fit a bleed fitting with lines to the swirl pot or header tank to them too.

Am I being too nit-picky?

richardpope50 · Post by **richardpope50** » Fri Sep 06, 2013 5:44 pm

Well that did not work. Bleed valve fitted to highest point and all pipes are full (they were probably full anyway but now I'm sure they are). So, my options seem to be:
1). Change water pump for a new one but I would be very surprised that a 44,000m engine needs one. The blades could be a bit rusted but to not circulate enough water?
2.) Fit jockey wheel to ensure pump is turning? I still think it is turning fine but I've made up a jockey wheel and now only need a new belt and fit it.
3.) Radiator not cooling enough? When fan is on the core is cold and air being blown is warm. When second stage fan is on (1,850 CFM) the air being blown is cool. The 12" fan covers the height 100% but clearly does not either side where no cooling happens but water going in is about 90 degrees and coming out is about 75 degrees measured with my multi-meter probe held against the ali pipes. So is 15 degrees enough of a drop?

The cabin heater pipes are all hot and the heater gives out heat so I doubt there is much air in that circuit. It's a thought, though.

Not really sure what to do next ....

JSF55 · Post by **JSF55** » Fri Sep 06, 2013 9:06 pm

Is that the right width belt on there ? that could cause it to slip , can you beg or borrow a temp gun to confirm your readings ?

Darkspeed · Post by **Darkspeed** » Sat Sep 07, 2013 8:31 am

If the problem persisits consider getting a straight discharge from the manifold fabricated remove the stat from that location and fit a radiator return hose thermostat housing.

JLR spent a lot of time developing that system and it works very well and gets away from the high hose issue.

http://www.ebay.co.uk/itm/LANDROVER-DIS ... 484667bdf3

richardpope50 · Post by **richardpope50** » Sat Sep 07, 2013 8:33 am

JSF55 wrote:Is that the right width belt on there ? that could cause it to slip , can you beg or borrow a temp gun to confirm your readings ?

Sort of. When I fitted the MegaSquirt trigger wheel it moved the crank pulley so I had to cut off a bit of the width.

It overheats at idle and there is no sign at all that the belt slips. It's tight and appears to turn fine.

Darkspeed · Post by **Darkspeed** » Sat Sep 07, 2013 8:57 am

If it overheats at idle - then clamp off every bypass hose so that the only path for water is the rad and see what happens - are all the rad fans turning in the correct direction for the fan blade design - ie pushers pushing / puller pulling - I know its an obvious thing but it has to be eliminated as a cause.

DaveEFI · Post by **DaveEFI** » Sat Sep 07, 2013 9:16 am

I've never known a belt to slip without it being obvious. Given the amount of power it has to transmit to turn a water pump I'd expect it to smoke if slipping for more than a short while.

On my SD1 which has a cross flow rad, if you remove the filler plug on the rad and the thermostat is open, you can clearly see the coolant sloshing around due to the pump. And that's while filling, so likely lots of air present too.

If you do suspect the pump, it's no big deal to whip it off for a visual inspection?

As regards the general layout of the cooling system, surely this isn't the only Dax with this exact engine?

Other thing to do would be to get the dash gauge sorted - or even rig up a temporary known good one using the sensor position by the thermostat. And perhaps whip out the MS one and check it really is accurate at 100C by putting it in boiling water while reading off the temp in TS.

Ian Anderson · Post by **Ian Anderson** » Sat Sep 07, 2013 11:05 am

How big is your radiator?

What car is itin?

Once moving is there. An exit route for the air that has been through the radiator ie past engine through fins oe open wings to wheel area or does it just form a dam?

Now on that you only have 1 by 12 inch fan

When fan only is running you only have 12 inch diameter of cooling from the complete area of the radiator.

Can you make a shroud to draw the air from a larger area of the radiator?

I have read somewhere that a 20 degree drop from inflow to rad to outflows from rad is required in most cases but cannot find the source now so your 16 degree seems a tad to low.

Iana

Darkspeed · Post by **Darkspeed** » Sat Sep 07, 2013 1:52 pm

If it overheats at idle - then clamp off every bypass hose so that the only path for water is the rad and see what happens - are all the rad fans turning in the correct direction for the fan blade design - ie pushers pushing / puller pulling - I know its an obvious thing but it has to be eliminated as a cause.

Darkspeed · Post by **Darkspeed** » Sat Sep 07, 2013 1:54 pm

If it overheats at idle - then clamp off every bypass hose so that the only path for water is the rad and see what happens - are all the rad fans turning in the correct direction for the fan blade design - ie pushers pushing / puller pulling - I know its an obvious thing but it has to be eliminated as a cause.