67 replies to this topic

[mullet]

Just to cover possibilities thoroughly.  Does the fan face the correct way and is it nicely under the shroud and reasonably close to the radiator face. 

Hi Earwax (great username!).  The fan's never been take off it since I've had it.  It's only the last year of the 9 years I have had it that it has had this issue (although always did run slightly hot).  The prior years I could do motorway driving for 100 miles without issue.  I've heard this before about fans being on the wrong way; strange they make a component that can be accidentally fitted both ways.  Ordering the new pump, but any other ideas I can check would be welcomed in the meantime.

[mullet]

Hello everyone.  I have the pump out now.  Here is a video of it:

https://1drv.ms/v/c/...S_gkxA?e=KxKNvG

It seems to turn reasonably well.  I am a novice, but doesn't seem damaged.  However, what I believe is a bypass is blocked with crud.  You see this at the end of the video.  A piece of rubber-like gasket sealant coupled with a build up of rusty particles.

 

Can this be the cause of my problem?  What is the consequence of this bypass being blocked?  Could it limit the hot water the new thermostat valve is bathed in, so it doesn't actually open in time and the engine overheats in a certain area (but, not right where the thermostat is)?

 

Should I re-use this pump once unblocked, with new gasket?  Or should I just get a new pump to be on the safe side? 

 

If narrow passages can block like this, makes me wonder if the radiator may be blocked, too.  One thing at a time, I guess....  

Edited by mullet, 09 June 2025 - 03:12 PM.

[Lplus]

Hello everyone.  I have the pump out now.  Here is a video of it:

https://1drv.ms/v/c/...S_gkxA?e=KxKNvG

It seems to turn reasonably well.  I am a novice, but doesn't seem damaged.  However, what I believe is a bypass is blocked with crud.  You see this at the end of the video.  A piece of rubber-like gasket sealant coupled with a build up of rusty particles.

 

Can this be the cause of my problem?  What is the consequence of this bypass being blocked?  Could it limit the hot water the new thermostat valve is bathed in, so it doesn't actually open in time and the engine overheats in a certain area (but, not right where the thermostat is)?

 

Should I re-use this pump once unblocked, with new gasket?  Or should I just get a new pump to be on the safe side? 

 

If narrow passages can block like this, makes me wonder if the radiator may be blocked, too.  One thing at a time, I guess....  

That pump looks horrible. The blocked bypass will slow the rate at which heat gets to the thermostat but not significantly.  In fact the blocked bypass will ensure more water goes through the radiator when the thermostat finally opens.  You already found a faulty thermostat, so replacing that and the pump should go a long way to fixing your problems.  You can try to clear the bypass hole in the head if you choose.

Edited by Lplus, 09 June 2025 - 03:20 PM.

[mullet]

 

Hello everyone.  I have the pump out now.  Here is a video of it:

https://1drv.ms/v/c/...S_gkxA?e=KxKNvG

It seems to turn reasonably well.  I am a novice, but doesn't seem damaged.  However, what I believe is a bypass is blocked with crud.  You see this at the end of the video.  A piece of rubber-like gasket sealant coupled with a build up of rusty particles.

 

Can this be the cause of my problem?  What is the consequence of this bypass being blocked?  Could it limit the hot water the new thermostat valve is bathed in, so it doesn't actually open in time and the engine overheats in a certain area (but, not right where the thermostat is)?

 

Should I re-use this pump once unblocked, with new gasket?  Or should I just get a new pump to be on the safe side? 

 

If narrow passages can block like this, makes me wonder if the radiator may be blocked, too.  One thing at a time, I guess....  

That pump looks horrible. The blocked bypass will slow the rate at which heat gets to the thermostat but not significantly.  In fact the blocked bypass will ensure more water goes through the radiator when the thermostat finally opens.  You already found a faulty thermostat, so replacing that and the pump should go a long way to fixing your problems.  You can try to clear the bypass hole in the head if you choose.

 

Thanks Lplus.  I'll get a new one just to be sure.  It looks manky indeed.  But does it look worn or broken to you?  I don't know what a good one looks like yet to compare.  I hope this nails the problem!

[imack]

Is the pump impeller fixed securely to the shaft? Can you rotate it while securely grasping the other end of the shaft?
I had a pump where the impeller only became loose on the shaft when the engine was hot.

[mullet]

Is the pump impeller fixed securely to the shaft? Can you rotate it while securely grasping the other end of the shaft?
I had a pump where the impeller only became loose on the shaft when the engine was hot.

I just tested as you advised.  Seems there's no slipping around the shaft (as I am accustomed to but that's another story).  But if symptoms only emerge when hot, I'll proceed to place an order for a new one.  If this doesn't work, I suppose the radiator will be the next thing to replace?

[Lplus]

 

 

Hello everyone.  I have the pump out now.  Here is a video of it:

https://1drv.ms/v/c/...S_gkxA?e=KxKNvG

It seems to turn reasonably well.  I am a novice, but doesn't seem damaged.  However, what I believe is a bypass is blocked with crud.  You see this at the end of the video.  A piece of rubber-like gasket sealant coupled with a build up of rusty particles.

 

Can this be the cause of my problem?  What is the consequence of this bypass being blocked?  Could it limit the hot water the new thermostat valve is bathed in, so it doesn't actually open in time and the engine overheats in a certain area (but, not right where the thermostat is)?

 

Should I re-use this pump once unblocked, with new gasket?  Or should I just get a new pump to be on the safe side? 

 

If narrow passages can block like this, makes me wonder if the radiator may be blocked, too.  One thing at a time, I guess....  

That pump looks horrible. The blocked bypass will slow the rate at which heat gets to the thermostat but not significantly.  In fact the blocked bypass will ensure more water goes through the radiator when the thermostat finally opens.  You already found a faulty thermostat, so replacing that and the pump should go a long way to fixing your problems.  You can try to clear the bypass hole in the head if you choose.

 

Thanks Lplus.  I'll get a new one just to be sure.  It looks manky indeed.  But does it look worn or broken to you?  I don't know what a good one looks like yet to compare.  I hope this nails the problem!

 

With all the corrosion and gunk in it, it can't be as efficient as a new pump.

[Earwax]

I concur with Lplus , the photo looks like the water pump has been pumping cruddy water for a long time. It is highly possible your symptoms ( overheating) are caused by a number of issues not just the one.

 

Blocks can 'leak' colour after lots and lots of flushes etc - as you said the water doesn't shift into the crud. Radiators can also have crud blocking some core tubes. ( The heater matrix is often an example of this but all radiators can have tubes narrowed or blocked it various stages.) Some flush regimes and products are better than others - your local guys will be able to advise if the one you used was good or not.

 

From your other post - I prefer to use new gaskets and for the thermostat -and  i smear of good quality RTV. One of the thermostat housing studs sometimes breaks into the water jacket and so RTY on threads is required anyway.

 

I couldn't see your file as a video ( just a picture) but the bypass type also have the small hose and two clips that I would redo when the pump is off ( small $)

 

On radiators - lots of opinions on cores / fins per inch / alloy/ new / etc  - but getting your existing one reconditioned - taken apart / rodded to clear tubes / fins straightened where possible/ soldered back together - is a great service but quite expensive.   If going alloy aftermarket - the key things to look at is overall width and height ( some touch the bonnet ) as well as core width. A while ago now but i think ones with overall width less than 57 mm and a core of 50mm NOT 40mm are well suited to the side sitting tank- and dont forget to check which way your outlets face..  I have an old timer Aussie made rad that was refreshed, a minispares one (new) and used to run an alloy one - and they are all capable of good cooling

[Designer]

Hi,

 

I might be wrong but if the bypass is blocked on the pump side then it would be a good idea to check if the bypass tube coming down from the head is also clear of any crud.

 

Paddy

[mullet]

I concur with Lplus , the photo looks like the water pump has been pumping cruddy water for a long time. It is highly possible your symptoms ( overheating) are caused by a number of issues not just the one.

 

Blocks can 'leak' colour after lots and lots of flushes etc - as you said the water doesn't shift into the crud. Radiators can also have crud blocking some core tubes. ( The heater matrix is often an example of this but all radiators can have tubes narrowed or blocked it various stages.) Some flush regimes and products are better than others - your local guys will be able to advise if the one you used was good or not.

 

From your other post - I prefer to use new gaskets and for the thermostat -and  i smear of good quality RTV. One of the thermostat housing studs sometimes breaks into the water jacket and so RTY on threads is required anyway.

 

I couldn't see your file as a video ( just a picture) but the bypass type also have the small hose and two clips that I would redo when the pump is off ( small $)

 

On radiators - lots of opinions on cores / fins per inch / alloy/ new / etc  - but getting your existing one reconditioned - taken apart / rodded to clear tubes / fins straightened where possible/ soldered back together - is a great service but quite expensive.   If going alloy aftermarket - the key things to look at is overall width and height ( some touch the bonnet ) as well as core width. A while ago now but i think ones with overall width less than 57 mm and a core of 50mm NOT 40mm are well suited to the side sitting tank- and dont forget to check which way your outlets face..  I have an old timer Aussie made rad that was refreshed, a minispares one (new) and used to run an alloy one - and they are all capable of good cooling

Thanks Earwax.  The video doesn't autoplay, annoyingly (seems the play button has to be pressed once loaded).  Now I have had the radiator out a couple of times, I understand this is not a difficult or time-consuming step.  So I'd like to see if the new pump changes anything and will get a few new things as you said.  Failing that, I'll turn attention to the radiator and get that out again.  I've done a fair amount of plumbing and soldering, but now I have seen how radiators get repaired this seems beyond the time I have to learn. 

 

Others have said bad timing shouldn't cause such rapid overheating.  I am not convinced the timing is great or if this should also be considered a heating factor or not.   I want to get it to a garage that can tune it (I've never done it, but want to shadow the mechanic doing it)...but I can't even drive it that far yet :)

Edited by mullet, 11 June 2025 - 07:09 PM.

[mullet]

Hi all.  I have the new pump in now, together with the recently bought 88 degree calorstat.  I also made sure the bypass was clear and with a new hose.  Fan definitely on the right way.  I will try to explain in chronological order what happened (#1 - 8) and then my questions.  I really hope I can make this clear, all done with the car still parked.  Sorry it seems I cannot put photos direct, getting an irritating "You are not allowed to use that image extension on this community" but no explanation how to get around it.  Photos in the links.

...

 

1. Engine started well.  The internal heater seemed to get warmer sooner, which I took as a good sign water was flowing better.  Heater was warm, never "roasting".

2. After 15 minutes, all going well until I noticed the internal heater started blowing cooler/almost not at all.  At this point, the needle started creeping up towards the H.

3. With the heater control, I pulled out (heating off) and pushed back in (heating on) and repeated a few times.  Now the heater was blowing no heat, no matter on or off.

4. Although I cannot be completely sure with the background engine noise, I think I heard some bubbling sounds (not in the engine compartment, but whilst seated in the driving seat).  I couldn't pinpoint where the sound was precisely coming from.  But I now kept the heater in the on position for a couple more minutes.  Needle getting closer to H.

5. I turned the engine off.  I touched the pipes to the internal heater and took note the temperatures were not uniform.  I hope this photo helps....

https://1drv.ms/i/c/...FmB_uQ?e=I2Dnar

 

6. Then I noticed the yellow coolant dripping from the heater itself (definitely NOT the pipes leading to/from the heater).  Not gushing out, just dripping and by the time the engine cooled I collected no more than about 20ml of the dripping coolant.

7. I turned the engine off.  I touched pipes in the engine compartment.  Pipes to/from internal heater the same temperature, hot but not painful to touch.  Pipe top of radiator the hottest.

8. with the engine cold, I checked the level of coolant.  It was to the brim before the test, but is now at this level, maybe 1cm above where the channels begin....

https://1drv.ms/i/c/...gU3YQQ?e=obV49F
 

QUESTIONS:

A. does the internal heater have a release valve if pressure is too much (so it may not be "leaking" and this was by design)?

B. I thought the "loss" of coolant level might be due to an airlock.  So if these are signs of the heater being airlocked, what can I do?  Pull this pipe off and with it being held higher than the radiator, fill it with coolant and as quick as possible, reattach?  Perhaps an assistant shaking the internal heater at the same time?....

https://1drv.ms/i/c/...88tJEA?e=7mEgxq

 

C. Is there something else I can try?  Or do I need a new rad/internal matrix?

[imack]

The sudden lack of temperature in the heater/pipes plust the bubbling noise suggests you just have an airlock. The coolant loss from the heater sounds like the matrix is leaking- assuming no leak from the hoses or clips.
Usually, running the engine at 3000ish rpm with water circulating through the heater will get rid of airlocks. Will probably then need topping up once cooled down.

[mullet]

The sudden lack of temperature in the heater/pipes plust the bubbling noise suggests you just have an airlock. The coolant loss from the heater sounds like the matrix is leaking- assuming no leak from the hoses or clips.
Usually, running the engine at 3000ish rpm with water circulating through the heater will get rid of airlocks. Will probably then need topping up once cooled down.

Thanks imack!  How long would it need running at 3000 for?  I will keep an eye on the matrix, see if it's OK once the air is out.

[imack]

Usually only until the thermostat opens. But, you may need to repeat the process if the coolant level has dropped once it's cooled down.

[mullet]

Usually only until the thermostat opens. But, you may need to repeat the process if the coolant level has dropped once it's cooled down.

Thank you.  I noticed when I squeezed one of the heater pipes coolant came out that was brownish with bits, too, at the connection point (maybe it was the source of leak after all).  Unlike the rest of the system - including the rad - that only has crystal clear coolant.  I drained the pipes to the heater and took a photo:

https://1drv.ms/i/c/...pgLeFA?e=Mx3uoL

 

With the heater out, I flushed.  Lightly brown water comes out.  I know I will probably get murdered for this, but I've left it standing with cleaning standard white vinegar for a few hours (nothing leaked out).  I'll drain, flush, refit and do the 3000 rpm this evening.

 

EDIT: as it was 31 degrees here - very unusual - it wouldn't have been a fair test for improvements taking the car out for a ride.  But roadside, the heater for the first time I have had it (9 years) was blowing roasting!  No leaks with heater (maybe airlock = more pressure = little steamy leak via hairlne crack?).  I did take top heater hose off and at highest of all levels  at the top of the engine, filled with coolant, thinking this should clear heater airlocks, and shoved on as quick as possible.  I also idled at 3000 until N-temp. 

 

I feel this isn't just my own shameful neglect, but that of prior owners and I am reversing the clock on this car thanks to this forum.  This was a big improvement.  Road will be the ultimate way to know.  Will try tomorrow if the weather isn't abnormally hot (to give a fair test).

Edited by mullet, 21 June 2025 - 05:01 PM.