Hmmmm

Asa some of you know I had a lot of problems with overheating when i first got the Tiger on the road. With a little help i finally got those sorted... and they were fine for about 18 months....

then a couple of months ago I was stuck in traffic and the temperature climbed to about 110 before a hose joiner let go and dumped all my fluid on the road

I repaired the join and filled /bled the system as usual but it just keeps on overheating every few miles.

I have since completely reworked the cooling... I removed the rad and flushed thoroughly with a hose pipe. moved the oild cooler so it is no longer in front of the rad. fitted a fan overrride switch just in case. replaced the pipe that runs from the bottom of the header tank to the pump so that it no longer has to climb up a couple of inches. and replaced the small bore tube that runs from the highest point in the system (top of the bend coming out of the thermostat housing) back to the header tank, this now is smaller diameter (10mm tube) and no longer rises up 3 inches above the hieght of the header tank... replaced the thermostat and drilled a couple of small holes in it as recommended by so many...

refilled and worked out the airlocks as best i can - the same way as i always have.

now i take it out and it overheats worse than ever! took it last night (in 2 degrees temp) ran for about 2 miles. got home and temp was 100. (fan was running)
as soon as i switched off the engine the pressure cap on the header tank was hissing like a 'good'n' for several minutes

SO>>>
my question is this.... what do I try now? I'm stumped!


to decribe my plumbing... I have a polo rad with a side header tank built in but the cap has been blocked so it is no longer a pressure cap. bottom hose goes to pump top hose to stat housing with a 10mm take off at the highest point going to the top of the header tank. bottom hose from header tank goes to pump. The heater outlet on the head is blanked off which i know causes a lot of debate but it has been that way all along and was fine for 18 months
fan is wired correctly and pulling air through rad. oil cooler is now above rad so not obstructing and as rad pretty much fills the nose cone there isnt much space for air to go anywhere but through it.

[Edited on 3-12-09 by DaveFJ]

Are you sure the water pump is still OK? Perhaps the internal pulley (water side) is broken/slipping, so the hot water isn't pumped trough your radiator ?

i have a big ass ali rad im thinking of selling, i can't get mine to temperatures above 95 even when im driving hard! might be worth fitting a bigger rad?

I'd be taking the water pump off and checking to see if the impeller was rotating with the shaft and not just spinning free.

Mike

Does the radiator get hot?

I would check for a cracked or warped cylinder head, or a blown head gasket.

What about the Thermostat????????

Is it working???

Can't help with your problem.
Other than to say I have the same Polo rad type setup on my 1800 Pinto.
And even with our summer temp of 35deg +
It never overheated, infact it rarely turned the fan on, unless stuck in traffic.

My first thought would also be the pump.
Assuming the thermostat was OK

david

Do you have a water pipe coming out the inlet manifold ? if not air could be traped in the head

Get a friendly local garage to rest your radiator water for hydro carbons (Costs about a fiver). Just to make sure your head gasket is ok.


Then I would do as suggested, checking the pump and the stat in a jug of hot water.

Personally, I would put a looped hose in place of the heater circuit and retest.

Pump was brand new when built 2 years ago.... but will pull it off and check...

rad is getting hot.

thermostat is new and i tested it before fitting.

As I said above, i know the pipe coming from the inlet manifold is the source of many arguments but it has been fine without one for 18 months so why should it become a problem now?

cheers

Dave

good idea about gas testing... will look into that

If i did put a loop in from the heater outlet i have nowhere to connect the other end to? I suppose I could connect a t piece to another pipe somewhere ? inlet to pump? or outlet from stat?

I dont know if this will help you this is how mine is piped
Big top rad - thermostat
big bottom - pump
rad over flow blocked
pipe out of inlet manifold - top of header tank
bottom of header tank to 5/8 pipe on the pump
small 8mm pipe on thermostat blocked
thermostat drilled 1/8 hole
The header tank has a top that lets air in and out [ sierra tank with yellow top]
Jacko

engine 2

[Edited on 3/12/09 by jacko]

checked timing?

checked mixture ? what do spark plugs look like colourwise?

what sort of grille do you have?

what size fan do you have and how fitted to radiator? i,e. have cowl - in front of behind radiator?

As above The front grill try the car without it
Andy w on here had trouble over heating till he removed the grill

but grille hasnt changed.... and was fine beore...

Its a fine mesh grille..

I have tweaked the tuning which may have made it a little leaner at idle.... plugs look perfect.

[Edited on 3-12-09 by DaveFJ]

do an insurance job and buy a westfield....

I had horrendous overheating with my MK earlier this year and ended up swapping the engine since when it's been fine. It used to boil after about 3 miles around town.
Re plumbing, I have:
Polo rad with no cap/side tank W302 IIRC.
Top hose: Stat to rad upper
Bottom hose: Rad bottom to 32-15-32 T-piece to big pump inlet and 15mm to header tank at rear of engine
Manifold looped to small pump stub
Small-bore hoses in 'T' configuration connecting rad bleed, stat bleed and header tank 'overflow'.
...so it runs totally enclosed and has been fine since the engine swap.
I think I had weak antifreeze in it last winter and there were some fairly severe frosts which may have set off a crack in the block or head - I haven't looked at the old engine to diagnose it.
But if yours has only started playing up recently it's quite likely head gasket or pump...
Try a compression test and have a look at the pump innards.
I've also shrouded between the rad and nose cone to persuade max air through the rad and cut vents in the bonnet to help the hot air to get out.
John.

quote:

---

Originally posted by DaveFJ
Pump was brand new when built 2 years ago.... but will pull it off and check...

rad is getting hot.

thermostat is new and i tested it before fitting.

As I said above, i know the pipe coming from the inlet manifold is the source of many arguments but it has been fine without one for 18 months so why should it become a problem now?

cheers

Dave

---

Problem already found/solved ?

Off with it's head!!

sounds like HG to me, but would probably check the pump first.

BTTT

Ok... for personal reasons nothing has been done to the tiger for the last 6 months

Now trying to get it ready for Stoneliegh and still need to resolve my overheating issues...

checked head gasket and pump - all fine

my brother visited last weekend and he has been a motor mechanic for 25 years... he sugested that my top 'bleed' hose was the issue.

The diagram below shows as close as possible my current setup and i have tried to show the relative heights etc...

the problem he believes is that the fluid level in my header is below the highest point in the system (not a lot i can do about that) but he suggested that my breather tube is actually allowing air into the system. he suggested i block off the pipe completely.

a quick check proves that when at idle very little water is in the top tube and when stopped the top tube is totally empty. squeezing the tube and releasing you can hear it sucking in air through the header tank pressure cap...

As a compromise I have installed a small valve (actually a gas cut off valve) along the bleed tube and a manual bleed valve at the highest point. I figure I can gets some revs going open the valve to bleed the system then close it before letting off the throttle.

now when stopped or idle the top tube seems much 'more full' so that seems promising!

so.... any thoughts?

and please... give up with the whole bypass argument!


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Absolutely no need to run a bypass on a pinto, mine was blocked off for 6000miles without any major overheating problems.

I think you have hit the nail on the head with the fluid level. The level in the tank *must* be higher than the highest point in the system.

If it is then the system will self bleed and makes everything nice and simple.

im concerned about this.

my bleed hose returns to ABOVE the fluid level on my expansion tank. The expansion tank is a standard rover item and has a "max" fluid level well below the top hose tail.

Will this mean my XE is likely to overheat?

Having the bleed hoses above the fluid level is no problem. Its when something like the top hose is above the level in the header you get problems.

The bleed hoses/return to header should be the highest point of the system.

phew.. i getcha ... sorry for hijack!

OK... lots of messing and it still overheats within a mile....

bitten the bullit and decided to start from scratch on the cooling so.....

new rad on order, new pump on order, thermostat housing cut in half and awaiting welding so it comes ou horizontal not sticking up in the air...

the stat housing will allow the highest point in the system to be the header tank.

new pump because i broke the pulley mount getting it off

new rad... never been happy with my old rad with the filler tank on the side so goin for a new one... spent half the day (when i should have been working!) researching and have come up with a bigger polo tank with the 8mm bleed at the top and a 430x320 core (old one was 377x320). measured the Avon nose cone and it should fit - just!

for reference I have gone for a rad for an 86-87 1.3 Polo
nissens part number 651631
oem part number 171.121.253.CJ
valeo ref 883819
I beleive this is the same as the VW303?


came across a few good sites in my searching so will list them, here for teh benefit of others searching this problem:

Nissens
an excellent site and gives cross ref to manufacturers part number

Spartauto
gives a lot of cross reference part numbers

Autokool
good site but slightly pricey

adrad
good site - cheap - well recommended

BuyParts Online
where I got my new rad. pretty cheap and a good range

will let you all know how i get on......

For those that are interested i can confirm that the rad I ordered above, does fit in the Tiger nose cone - just1 and sits vertically....

just fabricated a rad cowling to attach the fan to so to try and improve the flow provided by the fan

hopefully will get some new coolant hose thsi week and will be able to tell all how it went

To any interested, after a long period of head scratching I can finally say she is back on the road - overheating fixed - cross fingers!

took her out saturday and sunday - ragged her sensless and couldnt get her to go over 90 degerees

watch out for some piccies of the new 'stealth' Avon