Cooling issues.

General Chat About Cooling & Overheating

Moderator: phpBB2 - Administrators

jenko
Helpful or Confused
Helpful or Confused
Posts: 110
Joined: Tue Jul 19, 2016 3:07 pm

Cooling issues.

Post by jenko »

Im still not 100% happy with the cooling on the Seight. It seems that after the car is full warmed up, I end up with basically no water behind the thermostat.

Can someone advise...car has no heater, so currently the thermostat bypass (the connection just behind the thermostat housing) is 't' connected to the top feed on the header tank and the top of the rad. It's this part Im unsure about....I wonder if this is somehow allowing air to end up in the chamber in the net manifold behind the thermostat. Any ideas.


Building a westfield V8

User avatar
Ian Anderson
Forum Contributor
Forum Contributor
Posts: 2396
Joined: Sun Nov 19, 2006 9:46 pm
Location: Edinburgh

Re: Cooling issues.

Post by Ian Anderson »

From your description I read that when your engine cools it draws air in past the pressure cap and into the header tank. As the bypass pile is connected to the top at this stage it will draw air back along said pipe.

I would connect the bypass into the pipe from the bottom of the header tank so it always gets water. Or have the overflow from the header pressure tank going into a collecting bottle with the overflow pipe going beneath the level of fluid in said bottle, when it heats it will push excess fluid past the seal into the overflow bottle and when cooling the fluid will be sucked back thereby keeping the main system full.

Ian
Owner of an "On the Road" GT40 Replica by DAX powered by 3.9Hotwre Efi, worked over by DJ Motors. EFi Working but still does some kangaroo at low revs (Damn the speed limits) In to paint shop 18/03/08.

User avatar
ChrisJC
Top Dog
Top Dog
Posts: 5039
Joined: Mon Nov 20, 2006 1:13 pm
Location: Northants / Cambs
Contact:

Re: Cooling issues.

Post by ChrisJC »

I forget - which cooling system it yours based on? Have you got some pictures?

Chris.
--
Series IIA 4.6 V8
R/R P38 4.6 V8
R/R L405 4.4 SDV8

jenko
Helpful or Confused
Helpful or Confused
Posts: 110
Joined: Tue Jul 19, 2016 3:07 pm

Re: Cooling issues.

Post by jenko »

I will grab some pictures today

The system is a gems inlet manifold, on a newer type of water pump (the ones on the crank driven oil pump). But, it's very 'custom'...no heater, and in a Westfield. Drawing air in from the header tank would make sense, this is the only place I can think of that could do this. I suspect this goes back to the ill informed diagram I pulled from the inter web that was also completely wrong regarding the flow direction (see my other post!).

Im sure it's a simple fix, but I want to get this right, so appreciate the help.

Paul.
Building a westfield V8

User avatar
ChrisJC
Top Dog
Top Dog
Posts: 5039
Joined: Mon Nov 20, 2006 1:13 pm
Location: Northants / Cambs
Contact:

Re: Cooling issues.

Post by ChrisJC »

Yeah, grab some pictures. I am sure it can be sorted out!

Chris.
--
Series IIA 4.6 V8
R/R P38 4.6 V8
R/R L405 4.4 SDV8

jenko
Helpful or Confused
Helpful or Confused
Posts: 110
Joined: Tue Jul 19, 2016 3:07 pm

Re: Cooling issues.

Post by jenko »

OK, here are some pics:
This one shows the header tank from bottom to top (looking at the pic), the larger hose is the one that goes to the inlet manifold, then the hose that goes to the 't' piece, then the overflow.
IMG_2938.JPG
This shows the thermostat housing and the T piece (for the t piece, it connects to the header tank, the inlet manifold and the top of the rad):
IMG_2939.JPG
The connection to the top of the Rad:
IMG_2940.JPG
Building a westfield V8

User avatar
ChrisJC
Top Dog
Top Dog
Posts: 5039
Joined: Mon Nov 20, 2006 1:13 pm
Location: Northants / Cambs
Contact:

Re: Cooling issues.

Post by ChrisJC »

Apologies - I'm still a bit confused!
Is the thermostat at the top front of the inlet manifold?, i.e. where the top hose leaves the inlet manifold going to the radiator? Or is it in the bottom hose?
What inlet manifold is it?, it looks like an EFi one.

The big pipe from your header tank should go into the bottom hose - so water from it gets drawn into the engine. If you connect it to the front of the inlet manifold, the water will be pumped _into_ it!

If it's the EFi manifold, then there is a little vent pipe near the water temperature sensor. It's supposed to go to the hotspot in the throttle body, but if not, it should go back to the header tank. It's the highest point, and without it air will gather behind the thermostat.

This 'T' piece you have - it seems connect the header tank, the inlet manifold, and what else?

Maybe a list of pipes and where they go to/from would be helpful.

Chris.
--
Series IIA 4.6 V8
R/R P38 4.6 V8
R/R L405 4.4 SDV8

jenko
Helpful or Confused
Helpful or Confused
Posts: 110
Joined: Tue Jul 19, 2016 3:07 pm

Re: Cooling issues.

Post by jenko »

Inlet manifold is the EFI version:
This one:
inlet manifold.png
The thermostat is indeed at the top front of the manifold. The big pipe from the header does to into the inlet manifold just under the thermostat.

The vent pipe you speak of....goes back to the header tank, and also into the top of the rad.

If the large pipe should go to the bottom hose, then what would the connection point on the inlet manifold be used for?.

The more I dig into this, the more it feels like everything is completely wrong.....

Thanks for the help.

Paul.
Building a westfield V8

jenko
Helpful or Confused
Helpful or Confused
Posts: 110
Joined: Tue Jul 19, 2016 3:07 pm

Re: Cooling issues.

Post by jenko »

Just looked at a load of other diagrams, and I agree, I seem to be completely wrong...god only knows how I ended up getting it so wrong. looks I need one of these, and remove the thermostat from the inlet manifold (but why is there a perfectly machined cut out)......looks like a robotic heart!.
Screen Shot 2020-07-19 at 17.57.55.png
Building a westfield V8

User avatar
ChrisJC
Top Dog
Top Dog
Posts: 5039
Joined: Mon Nov 20, 2006 1:13 pm
Location: Northants / Cambs
Contact:

Re: Cooling issues.

Post by ChrisJC »

You've got a mixture of parts that were never together on a factory engine. It looks like you've got the Range Rover P38 style front cover (with the water pump that rotates off the back of belt, i.e. the opposite way to the crankshaft), and an earlier inlet manifold.

Not that there's any reason it can't be made to work.

The two outlets at the front of the inlet manifold are heater feed and thermostat bypass.

I think you have two options:
1. Keep the thermostat in the top hose. This means you need:
- Top hose from thermostat outlet to top of radiator.
- Bottom hose from bottom of radiator to water pump inlet.
- Blank off lower 19mm (ish) front outlet from inlet manifold.
- Top 19mm outlet goes straight down to 'T' into bottom hose. This is the thermostat bypass circuit.
- Header tank big pipe at the bottom goes down to 'T' into bottom hose as well.
- Radiator vent goes to top of header tank.
- Small outlet that is supposed to go to throttle body hotspot instead goes to middle of header tank.

2. Move thermostat to bottom hose.
This is the same arrangement as above, but the thermostat will have all of the ports you need instead of a bunch of 'T' pieces.
You should find it looks very similar to the picture below.
You will find it a bit of a bugger to fill with coolant though - I always take off the top hose and fill in both directions (i.e. engine and radiator!)

With the P38 thermostat, they only come in one temperature, which is about 95 !! I believe the Discovery 2 thermostat is cooler, but I don't know if it's got enough ports on.

Chris.
Screenshot from 2020-07-19 20-53-26.png
--
Series IIA 4.6 V8
R/R P38 4.6 V8
R/R L405 4.4 SDV8

jenko
Helpful or Confused
Helpful or Confused
Posts: 110
Joined: Tue Jul 19, 2016 3:07 pm

Re: Cooling issues.

Post by jenko »

Hi Chris..just to clarify, when you say ‘top 19mm hose’, do you mean the Connection coming up from the inlet manifold (originally meant for the throttle body hot spot).

I prefer option 1 as I have next to no room on the bottom hose.
Building a westfield V8

User avatar
ChrisJC
Top Dog
Top Dog
Posts: 5039
Joined: Mon Nov 20, 2006 1:13 pm
Location: Northants / Cambs
Contact:

Re: Cooling issues.

Post by ChrisJC »

Sorry!, just looked again. My bad. Try this:

1. Keep the thermostat in the top hose. This means you need:
- Top hose from thermostat outlet to top of radiator.
- Bottom hose from bottom of radiator to water pump inlet.
- Lower 19mm (ish) front outlet from inlet manifold goes straight down to 'T' into bottom hose. This is the thermostat bypass circuit.
- Header tank big pipe at the bottom goes down to 'T' into bottom hose as well.
- Radiator vent goes to top of header tank.
- Small outlet that is supposed to go to throttle body hotspot instead goes to middle of header tank.

Also, your header tank does need to be at the highest point. Worth being clear about that.

For the record, on the earlier timing covers, the water pumps had extra inlets on them which moved to the thermostat on vehicles with the timing cover you have. This is why you need to add extra T's to the bottom hose as you have neither thermostat housing in the bottom hose nor water pump with the extra inlets.

Chris.
--
Series IIA 4.6 V8
R/R P38 4.6 V8
R/R L405 4.4 SDV8

jenko
Helpful or Confused
Helpful or Confused
Posts: 110
Joined: Tue Jul 19, 2016 3:07 pm

Re: Cooling issues.

Post by jenko »

Ok..sounds good..only one that won’t work, is the connection to the middle of the header tank. This one is the overflow, so only works if the pressure in the header tank goes too high. I guess ‘T’ ing it to the rad vent......
Building a westfield V8

User avatar
ChrisJC
Top Dog
Top Dog
Posts: 5039
Joined: Mon Nov 20, 2006 1:13 pm
Location: Northants / Cambs
Contact:

Re: Cooling issues.

Post by ChrisJC »

I think so. Worth a try at any rate - I'm sure it will be miles better!

Chris.
--
Series IIA 4.6 V8
R/R P38 4.6 V8
R/R L405 4.4 SDV8

jenko
Helpful or Confused
Helpful or Confused
Posts: 110
Joined: Tue Jul 19, 2016 3:07 pm

Re: Cooling issues.

Post by jenko »

Another thought - Regarding the outlet to the 'throttle body hot spot' on the top of the manifold....I've looked at the diagram and I can see no reason why this is even needs to be connected. The larger 16mm connector should do a perfectly adequate job of by passing the thermostat. What do you think?
Building a westfield V8

Post Reply

Return to “Cooling Area”