Jump to content

New Jeep Cherokee 2015 owner, coolant flow issue


Lumen

Recommended Posts

  • Platinum Member

Hi all,

 

This forum looks like a cosy place to be, thank you for the ad.

I recently started to experience issues with my Jeep Cherokee 2015 (Fiat’s M-Jet Ii 2.2 diesel engine)

Heater started blowing cold air and car was overheating intermediately during the first 20 min or so of the journey. Taken it to the Jeep Garage, they diagnosed bubbles in the coolant and said that coolant isn’t flowing properly. The cam belt and water pump was replaced and vacuum filled (car has done 70k miles and belt wasn’t charged before) That didn’t help, thermostat assembly was then subsequently replaced and system was once again refilled. That also didn’t help. I notice small coolant lose (coolant moved to the min line when it was in the middle) So I taken the car to the independent garage to check for any leaks and had the coolant flushed, that also didn’t help. 

 

Now I drive with coolant temp on the main screen and noticed a pattern. Car starts fine hot air blowing in the first 10 min of the journey or so, I then notice sudden cold air blowing, so I know engine is about to start getting hot, as it feels like coolant stops flowing, I then have to pull over or let the car roll in neutral and watch the coolant temp climb to 100 plus, it gets to 120 at times. This is where it gets sketchy, coolant can purge through in seconds at other times minutes before it starts flowing and temp drops to 80 again and I can drive.

This looks like there’s air in the system that eventually gets pushed through and coolant starts flowing again, but the system got refilled 3 times now and garages said there were no sign of any coolant leaks what so ever, so I’m lost now.

 

Has anyone exercised anything like this before? Any advise would be much appreciated.

 

PS. There's no contamination signs in the coolant expansion tank or condensation/white froth on oil fill cap, so it doesn't look like internal leak either.

 

Thanks,

Lumen

Edited by Lumen
Link to comment
Share on other sites

  • Platinum Member

If you have already had the coolant pump and thermostat changed I guess it could be a head gasket failure or cracked cylinder head. Check oil for contamination with coolant and coolant for contamination with oil.

  • Like 1
Link to comment
Share on other sites

  • Platinum Member

agree with Vince, could be head gasket failure, compression is going into the water system and vice versa, possibly get the system pressure checked, 

  • Like 1
Link to comment
Share on other sites

  • Platinum Member

Whilst, sadly,  agreeing with V and Frosty, I always consider the simple possibilities. The only one I can think of that could have been missed is an air lock. Just refilling doesn't always do the job!  I've had just these sort of peculiar things on odd occasions over a lifetime. When the system fluid is  changed , I do things like pull off connection pipes and flush/fill with a hose and pop back on quick just to make sure no air locks. I would certainly do this with the heater pipes etc. Look out for pipes etc where they rise up higher as well, this is where you can get big air bubbles trapped.  Have any pipes been rerouted/replaced ? Maybe not correctly. Naughty mechanics do this just to save time refitting.

 

Just a thought. good luck.

Edited by digger
  • Like 2
Link to comment
Share on other sites

  • Platinum Member

Thank you for prompt reply chaps.

There's no contamination signs in the coolant expansion tank or condensation/white froth on oil fill cap, so it doesn't look like internal leak either.

Link to comment
Share on other sites

  • Platinum Member
1 hour ago, digger said:

Whilst, sadly,  agreeing with V and Frosty, I always consider the simple possibilities. The only one I can think of that could have been missed is an air lock. Just refilling doesn't always do the job!  I've had just these sort of peculiar things on odd occasions over a lifetime. When the system fluid is  changed , I do things like pull off connection pipes and flush/fill with a hose and pop back on quick just to make sure no air locks. I would certainly do this with the heater pipes etc. Look out for pipes etc where they rise up higher as well, this is where you can get big air bubbles trapped.  Have any pipes been rerouted/replaced ? Maybe not correctly. Naughty mechanics do this just to save time refitting.

 

Just a thought. good luck.

Thank you for your reply digger. I'm inclined to suspect that cooling system is either sucking air somewhere or leaking coolant very slowly.

I see there is UV dye for coolant out there, so considering adding that and seeing if there are any leaks with UV torch.

Has anyone had previous experience with UV dye, would advise or discourage adding 25ml to the coolant?

 

  • Like 1
Link to comment
Share on other sites

  • Platinum Member

Check for damp carpet in the front. If the heater has failed it could be leaking and sucking in air there.

 

It is likely the turbo on your engine is water cooled. If it has inlet and outlet pipes for coolant (the outlet is usually higher) check them. A crack in the turbo's cooling jacket is another potential cause of a mystery internal leak.

 

I have not used UV dye on coolant before, but it worked great tracking down an air-conditioning leak. Externally leaking coolant normally leaves a visible stain when it dries or it shows a spurt of water or steam when running.

 

On a petrol engine, antifreeze that leaks into the combustion chamber can cause the fuel mixture to go rich when the silicon in it starts to contaminate the oxygen sensor. The tip of the sensor will go white when this happens, I don't know if something similar happens to a diesel NOx sensor.

  • Like 1
Link to comment
Share on other sites

  • Platinum Member
42 minutes ago, V said:

Check for damp carpet in the front. If the heater has failed it could be leaking and sucking in air there.

 

It is likely the turbo on your engine is water cooled. If it has inlet and outlet pipes for coolant (the outlet is usually higher) check them. A crack in the turbo's cooling jacket is another potential cause of a mystery internal leak.

 

I have not used UV dye on coolant before, but it worked great tracking down an air-conditioning leak. Externally leaking coolant normally leaves a visible stain when it dries or it shows a spurt of water or steam when running.

 

On a petrol engine, antifreeze that leaks into the combustion chamber can cause the fuel mixture to go rich when the silicon in it starts to contaminate the oxygen sensor. The tip of the sensor will go white when this happens, I don't know if something similar happens to a diesel NOx sensor.

 

Thank you for replying and your time taken to read my comments V.

I will check the carpets and turbo jacket this evening, those two certainly something I didn't think about.

Much appreciated.

Link to comment
Share on other sites

  • Platinum Member

Interestingly I’m having exactly these symptoms on my 96 XJ TD but with one added issue

 

As yet not resolved as it’s hissing down.

 

I bought the car with a known cooling problem - I took a risk as the price was good and no sign of HGF.  And there still isn’t - but I accept that this may well be the issue.  But no oil in water or vice versa.

 

The issue when I bought it seemed to be air lock(s) - I cured it for nearly a year by fitting a bleed valve in the Top Hose and two more smaller ones in the heater matrix hoses. (Also fitted new radiator) Careful flushing, and venting air via the three air bleed valves solved it.  Yes, fitting these provides three more potential leak sources but if done properly they are a real benefit in eliminating airlocks.

 

About a month ago I started suffering a lot more internal condensation on the front windows and windscreen.  Didn’t think much of it as this Winter is a wet one and last winter was my first with the XJ and it spent the winter sorned and getting the rusty front floor repaired.

 

Then, a few weeks ago I started to hear chirping from the water pump, shortly after which exactly the same symptoms - loss of heat from the car vents and temp gauge rising.  
 

Pulled over, topped up, limped home no problem.

 

I isolated the heater matrix (easy as all I had to do was undo the heater bleed valves and connect the engine side tubes across). I then flushed just the heater matrix and got a huge amount of crud out.  I haven’t pressure tested yet but it’s on the list.

 

The water pump IMO has been knocked out by the crud in the coolant from the existing matrix - and the old radiator, now replaced.  My thinking is if one was totally shot, why would the heater matrix be any different?

 

Only this morning i used our Karcher condensation device to suck up the condensation in the windows and removed a heck of a lot - and the front carpets are wet.  It’s possible that a weeping heater matrix has been a long term issue - hence the floor rot.

 

So this to me indicates two interlinked problems :-

a) the heater matrix is rusty as heck and this crud knocked out the water pump

b) Lack of water flow allowed overheating and the increased pressure finally “popped” the weeping matrix.

 

New water pump being fitted if and when we ever get a dry day.  Then we will test and hope it’s not a HGF.

 

When it gets warmer the dash comes out and a new matrix fitted. The good advice from the guys on here 👍is to get a good custom one made rather than fit a poor off the shelf one 

 


 

 

Link to comment
Share on other sites

  • Platinum Member

The older VM diesel XJ had a reputation for cracking heads. I think it was more common on No.4 and No.3 . Back in the day, I would encourage people to always do a 1 or 2 minute turbo cool down at engine idle before shutting down. This helped reduce dissimilar cooling between the front and rear of the engine and helped prevent wear on the turbo spindle.

 

http://www.vmdieselspecialist.com/cylinder-head-service/

Edited by V
  • Like 1
  • Thanks 1
Link to comment
Share on other sites

Before you commit to getting the head gasket done, ask the independent garage to bypass the EGR cooler. See if that solves the issue. If it does, replace the cooler. 

  • Like 3
Link to comment
Share on other sites

  • Platinum Member

Chaps,

 

Is there pressure relief valve or another safety device on coolant expansion tank by any chance?

 

I’ve added the UV dye and this evening noticed fresh coolant marks right underneath the expansion tank. 

 

DFDAF7E4-EED4-4DF8-8A75-7F5A14F6B33E.jpeg

E7BADC47-DC65-4E2D-946F-A878B86C81B3.jpeg

  • Like 2
Link to comment
Share on other sites

  • Platinum Member

I had a 2.5 VM. I've been convinced for years that they are little different to other motors with Iron block and alloy head. ie essential to use and change correct antifreeze etc. However the VM2.5 was originally designed to be used in boats and barges and run at a steady speed all day everyday very reliably. My guess is that those who overrev, overheat (Vs comments above v interesting because in a boat its unlikely to have a bulkhead wrapped around the back of it), (try to !) drive fast etc exacerbate the problem. The combination of both issues can cause problems.

Have you checked for pipe/joint  leaks etc?  I've even had cracked/pinhole rot plastic reservoirs etc(you can reseal these by removing reservoir/cleaning the crack then get some similar plastic/ polythene whatever. Heat up or even light so it melts hot drips  onto the crack. Another old trick! Be careful fire risk )

Always look for simple first! Where is that leak coming from?

I don't know about the existence of a pressure relief and I can't remember re my XJs but I'd be surprised if there is none.

An easy old fashioned check for a blown head gasket is to simply take off  the highest cap (cold) and start up and run  without it. Ok you get a bit of water sloshing out, and be careful! However, if the gaskets blowing into the coolant system, the water will shoot up in quantity under pressure from the head leak sometimes like a fountain! Its not infallible but its a good clue.

I've not stripped a VM 2.5 . You should research where the head gaskets tend to fail (cylinder head to coolant where? etc) Some engines blow between cylinders and no water leaks. ( we did an Austin Champ motor long ago. each pair were joined. It was low on power but still ran fine!)

Edited by digger
  • Like 1
Link to comment
Share on other sites

  • Platinum Member

Have you determined if the leak is from the hose or the bottle yet?

 

It is possible to repair cracks in reservoir bottles using plastic welding. It's worth trying if you cannot easily find a replacement part. If you have not done it before it is best to practice first on something similar that is already scrap.

 

There are two techniques that I have used before for heat application: non-contact and contact. For both you need to be able to target the heat directly to the affected area. There are specialist tools available for this but you can be successful with a hot air gun or a soldering iron. Don't use an oven.

 

The component that you need to repair is likely to be made from HDPE. Fortunately, a lot of household or food products come in HDPE bottles so these can be used as filler material and for practising. My windscreen washer bottle has numerous patches made from plastic milk bottles. HDPE and ABS can be repaired with these techniques. Cable tie cut offs can also be used as filler. Wire can be used as embedded reinforcement.

 

 

 

  • Like 2
Link to comment
Share on other sites

  • Platinum Member
On 11/01/2023 at 08:27, digger said:

Whilst, sadly,  agreeing with V and Frosty, I always consider the simple possibilities. The only one I can think of that could have been missed is an air lock. Just refilling doesn't always do the job!  I've had just these sort of peculiar things on odd occasions over a lifetime. When the system fluid is  changed , I do things like pull off connection pipes and flush/fill with a hose and pop back on quick just to make sure no air locks. I would certainly do this with the heater pipes etc. Look out for pipes etc where they rise up higher as well, this is where you can get big air bubbles trapped.  Have any pipes been rerouted/replaced ? Maybe not correctly. Naughty mechanics do this just to save time refitting.

 

Just a thought. good luck.

Completely agree with this, with air locks, if you can fine the highest point of coolant system and bleed the air from a suitable position. Not always easy I grant you.

 

A possible way is park on a steep hill, so the engine is angled, coolant tank at the top/highest position, hopefully with the engine angled any air locks have an opportunity to work themselves out of the system. Turn engine off. Mark the position of the coolant level, check again in 30 mins and see if it has changed. if all the coolant disappears, then you had air locks in the engine, refill coolant tank (30 min cooling down period). Then see how it does. 

 

if the coolant is dirty/sooty, then a exhaust gas leak to the coolant system, I’ve seen that a lot on engines, but large industrial engines. This is common on turbo charger cooling systems. 

Edited by Caroline12
Extra info
  • Like 1
Link to comment
Share on other sites

  • Platinum Member

Air locks - repeatedly squeeze bottom hose, if easy to get at, with radiator cap off. Any air should bubble out. Has worked for me!

 

XJ & VM engine - my old XJ blew one of it's cylinder heads. Head cracks between water gallery and exhaust outlet. Poor design, too close together, or poor casting when manufactured? IMO. But as digger says, constant temp swings from cold to hot etc stresses head?

No external signs of the problem, just an extra thirst for water! I managed to get mine home from near Southampton with 2 or 3 stops to top up water!

  • Like 2
Link to comment
Share on other sites

  • Platinum Member

Hi V, 

That's amazing, your info about plastic welding that you 've posted. 

I had no idea of any of it and had forgotten my trick,not having used it for years. The first time I did it , I was asked in the 60s if I could repair a bottle form ,I think, an old Bristol!  As you suggest , I experimented before I did it. What I actually did ( not recommended,do not try this at home etc) and since was to light a roll of suitable plastic with a match. It smelled horrible but dripped 'bombs' of molten plastic onto the damage and worked!  Amazing,seemed to last as well. In those days if no part was available you either found a way to fix it or it was tough!

 

Hi Caroline, I have fitted bleed nipples in systems in the past.  Folk  might like to know that you can buy suitable 'bleed ' valves in any plumbers merchant which are easily installed in high heater pipes etc You can also get them in Motor Sport  places like 'Demon Tweeks' , dearer but car specific and made from alloy. For even more saving ,racing, I have just bought nipples from merchants and soldered them into suitable size copper pipe!

  • Like 1
Link to comment
Share on other sites

  • Platinum Member
On 12/01/2023 at 08:14, Ludders said:

Before you commit to getting the head gasket done, ask the independent garage to bypass the EGR cooler. See if that solves the issue. If it does, replace the cooler. 

 

It looks like the coolant is leaking underneath the inlet engine side clamp.

Can somebody advise where can I get the replacement hose clamp? 68138 725AA

Thank you

 

Coolant Res.jpg

Link to comment
Share on other sites

  • Platinum Member

Try local Jeep dealer parts counter.

They are listed on rockauto.com but currently out of stock

Can a generic hose clamp do the job (wormdrive or spring)?

 

  • Like 1
  • Thanks 1
Link to comment
Share on other sites

  • 4 weeks later...
  • Platinum Member

Hi everyone, thank you for all the contribution and help on this.

 

Weather was somewhat warmer this weekend and I've managed to take the air filter and coolant expansion tank off and discovered where the traces of coolant were coming from.

As it turns out the coolant was spitting out from underneath the expansion tank through an overflow hole.

There is a small overflow hole just underneath the expansion cap, so it looks like coolant gets to that level and then overflows, so it doesn't flow down from expansion tank.

What could be causing a clog in any of the pipes/components down from the expansion tank, is there a typical culprit given that water pump and thermostat have already been replaced and I know coolant system holds pressure, as when I open expansion vessel cap, air rushes out along with some coolant from the top pipe into the tank.

 

I'm baffled by this any further advise would be highly appreciated guys.

 

 

 

 

 

Exp.jpg

Link to comment
Share on other sites

  • Platinum Member
On 10/01/2023 at 21:39, Lumen said:

Taken it to the Jeep Garage, they diagnosed bubbles in the coolant and said that coolant isn’t flowing properly.

Bubbles are usually a sign of combustion gases getting into the engine's coolant system. It can also be from air ingestion anywhere along the engine cooling and cabin heating system.

 

There are a variety of combustion gas detection tools that work on the principle of passing 'air' from the coolant reservoir or radiator through a column of special liquid that changes colour when a higher level of carbon dioxide is present. Some of the tools you can reuse the fluid afterwards (E.g. Laser 5524), some you can't. I think it would be worth doing this test yourself.

 

If the test fluid changes colour, then CO2 from combustion could be getting into the coolant from any component where both combustion gas and coolant are present.

  • Cylinder head & gasket
  • Engine block
  • Liquid cooled EGR valve
  • Liquid cooled turbo

If there are bubbles in the coolant and CO2 could not be detected then it is an air ingestion problem on the cooling system. Here is a list of some to check.

  • Failing core plug - should show a coolant leak particularly with UV
  • Outer head gasket failure - failed from coolant jacket to atmosphere, possible warped head from a previous overheat
  • Perished coolant hose
  • Damaged coolant hose fitting on component
  • Out of round hose clamp or hose fitting
  • Loose or missing hose clamp
  • Cracked coolant system component
  • Porous aluminium coolant component
  • Any cooling system gasket
  • Heater core
  • Radiator core
  • Liquid cooled oil cooler - filter head cooler or in main radiator
  • Like 1
Link to comment
Share on other sites

  • Platinum Member
32 minutes ago, V said:

Bubbles are usually a sign of combustion gases getting into the engine's coolant system. It can also be from air ingestion anywhere along the engine cooling and cabin heating system.

 

There are a variety of combustion gas detection tools that work on the principle of passing 'air' from the coolant reservoir or radiator through a column of special liquid that changes colour when a higher level of carbon dioxide is present. Some of the tools you can reuse the fluid afterwards (E.g. Laser 5524), some you can't. I think it would be worth doing this test yourself.

 

If the test fluid changes colour, then CO2 from combustion could be getting into the coolant from any component where both combustion gas and coolant are present.

  • Cylinder head & gasket
  • Engine block
  • Liquid cooled EGR valve
  • Liquid cooled turbo

If there are bubbles in the coolant and CO2 could not be detected then it is an air ingestion problem on the cooling system. Here is a list of some to check.

  • Failing core plug - should show a coolant leak particularly with UV
  • Outer head gasket failure - failed from coolant jacket to atmosphere, possible warped head from a previous overheat
  • Perished coolant hose
  • Damaged coolant hose fitting on component
  • Out of round hose clamp or hose fitting
  • Loose or missing hose clamp
  • Cracked coolant system component
  • Porous aluminium coolant component
  • Any cooling system gasket
  • Heater core
  • Radiator core
  • Liquid cooled oil cooler - filter head cooler or in main radiator

 

Thank you for such detailed and extensive reply V, much appreciated, I'll order the CO2 test kit and take it form there.

 

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

guidelines