Ran 300TDi low on coolant ~1300km

I hope my first post here doesn't start as badly as my first land rover purchase.
Ill try to keep it short (After writing the post I realize it didn't succeed with keeping it short).

I bought my first Land Rover Discovery I 300 TDi 1998 with about 220000km on the meter a few days ago in the south of Sweden, I myself live in the north part of Sweden. The car was owned by a older man and he had owned it since new. The car looked good, expect for more rust than I expected and some minor issues. It had just passed a inspection so it was drivable. It had been regularly serviced and engine ran fine. Did a quick check of the oil but nothing fancy before I started the drive home, a drive of approximate 1000 km. Now afterwards I realize it would have been a good thing to check coolant level which I forgot. It was later on the day and fairly cool outside so no need for AC. I had just done minor readup on the 300 TDi and knew I should look out for overheating so keept an eye on the engine temperature meter which stayed around center the whole trip.

After a while it started to get colder outside so I cranked up some heat and the fan, to my disappointment the heater only gave me semi warm air. But I managed and thought to myself that its probably an easy fix. Cruised at around 100-110 km/h most of the trip and everything went just fine all the way home. Calculated that during the trip the car consumed about 10 liter / 100km which I think is fairly ok. The next day I drove the car to my parents about a 200km drive. The last maybe 50 km I started the AC and the drive went just fine. Until I parked the car at my parents and it idled for maybe 3 minutes. I hear something pouring out underneath the car, so I shut the engine of popped the hood and saw that the header tank had split. Just felt like **** My Life. Didn't remember to check the temperature gauge before shutting the engine off. Did a quick Google and found some possible issues and was hoping for the pressure valve on the header cap. Started by ordering headertank and cap and replaced these.

When I removed the cap on the thermostat housing to fill it I noticed it was really wear out but it was sealing as it was suppose to. I filled up everything with the car parked up hill and then filmed with a thermal heat gun to check that the radiator was working and not clogged up. Looked good, still had trouble getting heat into the matrix but decided that maybe it only need to be driven a bit. It ran and no overheating after a drive but still no heat in the matrix, but it was warm so didn't bother with it. Really needed to move my trailer which was the reason I went to my parents house in the first place so hooked it up and turned on the AC and drove maybe 40km and decided to do a quick stop and inspection just to see that coolant was staying in the right places. To my disappointment I found coolant dripping from the header cap, drove 2 more kilometers to a friend and the engine was overheating.

Parked car in a steep up hill and took the cap of the thermostat housing and there was no coolant in there. Started filling it up and noticed it was slowly dropping and found a leak somewhere behind the water pump. Started Googling and the more I Googled I realized that the more I had ****ed up...

Heater matrix hoses are located high and because the coolant had dropped around the level of the waterpump no coolant had entered the matrix. But whats worse is that the matrix is connected in series with the head so probably no coolant running through the head. And if the coolant has been below the waterpump perhaps no coolant pumping around the engine. Temperature sensor is high so probably not submerged in coolant so always showing way to low... Now I really felt like FML. I came to the conclusion that most likely a leaking P-Gasket. Filled the coolant system up and quickly closed the cap on the thermostat housing got the heaters to work so no air stuck there anymore. Drove to my parents with the heating on so that I could notice if the cooling dropped to much. No problems. Parked the car and ordered new p gasket and some other stuff.

I will start by replacing P-Gasket and inspect waterpump. Later on I plan to replace headgasket and mill it.

Conclusion
But now I'm worried that I have made substantial damage to my engine running it for a long period with coolant low? I would assume that I have been driving it at least 1300km with low coolant, and how much previous owner has driven it with low coolant I don t know. And perhaps the coolant wasn't able to boil because it was to low except for when the AC was on? Don't know if the AC could make it run hot or if that was just a coincidence? The engine runs fine but is there any checks I can do to see if any damage has been done? Don't want to start pouring in money and time on a engine that I have damaged beyond repair?

Perhaps there is nothing to worry about, if the engine runs fine its fine?

Put new pump & p gasket on,then test again. You may not have damaged the head gasket yet.
Make sure when you remove the bolts for the pump,you put these back in the correct holes. They are diffent lengths

Good luck

Its probably fine, I ran mine with a failed water pump & a snapped fan belt plus a busted hose. (duck taped) & removed the rad cap. I was towing a mini digger on a twisty B road steam was pizzing out of it & topped it up with sea water an drove it until the temp light was just under the red then waited until it cooled down, done this to get home. All parts changed & flushed it ran perfect for another 2 years.

Glad to hear not everything is lost

Has anyone tried to remove the fan without the special "32mm Viscous Fan Spanner tool"? I have ordered one but unsure if it will arrive before the weekend.

I am not experienced but I have changed the water pump with a guy who knew what he was doing. He suggested I replace the bolts too - which I did.

Also consider fitting a low coolant alarm - mine has saved me at least once.

And good luck with it - I hope everything is in good condition and you get it up and running.

I only ordered the long bolts that mount the waterpump bracket to the block. What Ive read up they tend to seize and then snap, really hope it doesn't happen to me. Hope that will be enough. I havent had time to look up a good source of parts here in Sweden so these parts come from Spain and take a while before they arrive so hope I dont need to order anything else to get it running. Found a lot of good UK sites but dont know how much customs will be added to the price and how long customs will hold the packet.

God suggestion regarding the alarm, I have actually been looking at the Madman EMS3 kit which I plan to install, but first I need to get all the must do things out of the way before I get carried away I would like to complement it with a pressure sensor for the coolant system, think that would be really good but it lacks more inputs so maybe ill just put an analog meter for that.

Replaced the P-gasket, it had more or less disintegrated. Also checked the waterpump and it looked ok, did only have a new gasket for the pump so replaced it. Put everything together and ofc the waterpump started leaking from the weep hole. The good thing is that I now know how to get everything apart.
But do I need to replace the P gasket again when changing the pump? Because the 3 bolts holding the p gasket in place need to be removed.

Bit of a late reply, but I think I would personally replace a gasket rather than hope you haven't damaged it.

Dr Strangeglove said:

Bit of a late reply, but I think I would personally replace a gasket rather than hope you haven't damaged it.

Click to expand...

I haven't had time to replace the pump yet, have all the part ready. Ordered a P-Gasket also and will replace it just to be on the safe side. Only pump I could get hold of in such short notice was a Britpart. Dont know if these are reliable, the seller told me he haven't had any problems with them but reading other threads makes me a little bit worried. Think Ill get myself a genuine one and replace it later on.

I think I used the metal P gasket and a smeer of hylomar as I believe it is a better gasket.

Changed waterpump and gaskets. But I think I still have air stuck in the heater because I can hear some bubbling there when I rev the engine. I parked the car uphill and topped it up from the thermostat housing, also ran the engine without the plug on the thermostat housing. The heaters in the car were turned to max. But the air doesnt seem to want to get out. At what angle should the car be parked? I guess the air is stuck in the hose near the back of the engine compartment that goes to the heater, when I parked the car the thermostat housing was above this hose.

Should the coolant always be all the way up to the plug in the thermostat housing? My seems to drop a little after I drive the car, could be because some air is finding it way out from the heater, maybe a small leak somewhere in the system or maybe the head gasket that is damaged. After turning off the car I have pressure in the coolant system, even a while after it has been parked.

At least the car is derivable right now which is a great success

The 300tdi engine should be easy to fill up with water, it self bleeds, did you put a hose pipe on the pipe inlets for the heater to flush out any crap. Previous owners love RTV gasket but put too much on. It then squishes into the inside and blocks things. Mine was terrible when I first got it. Water pump and P gasket always do at the same time and never leave it leaking for long as that causes rust and snapped bolts. On a side note I've done loads and never had a bolt snap yet but I always replace with new. Buy the most expensive pump you can. So many cheap ones that don't last a year.
I love hylomar too but I find that the P gasket is the only place to benefit from RTV. Metal gasket and just enough RTV both sides of gasket. Remember to leave to cure for ten minutes before assembling.
There is a small pipe going from the expansion tank and up and over the cam belt cover. There is a Y junction on it. That plastic connection is an air separator. Maybe that needs replacing. Is the pump working properly? I always fill with the car level.
Remove both plugs on stat housing and rad.
Fill tank until at the top of the rad and fit plug. Then fill tank until at stat housing. Fit plug. Take for a drive. A good drive. Then check and fill the tank to the level. It should be as simple as that.
Only use de-ironised water with coolant. It keeps inside in good condition from corrosion.
If you can hear bubbling when you rev that's a red flag for head gasket depending on if you hear inside or out. Remove expansion tank cap and start engine. Then standing at front rev engine using injection pump linkage while looking in tank. If the reving causes bubbles then head gasket suspect.
Buy a snif test from Amazon to confirm.
These engines are very hardy and nearly all the time it will only fail the head gasket. That said the cylinder head can crack in the exhaust ports but that usually results in leaving a faint trail of steam.
I am more concerned your expansion tank split. This could mean the head gasket has failed from cylinder to water which results in compression entering the coolant and building up pressure which in turn can blow seals. Like P gasket and water pump. And also damaging the expansion tank if the caps pressure release is not working.
Like I said earlier, test the tank for bubbles and do a sniff test.

Good luck

currymunster said:

The 300tdi engine should be easy to fill up with water, it self bleeds, did you put a hose pipe on the pipe inlets for the heater to flush out any crap. Previous owners love RTV gasket but put too much on. It then squishes into the inside and blocks things. Mine was terrible when I first got it. Water pump and P gasket always do at the same time and never leave it leaking for long as that causes rust and snapped bolts. On a side note I've done loads and never had a bolt snap yet but I always replace with new. Buy the most expensive pump you can. So many cheap ones that don't last a year.
I love hylomar too but I find that the P gasket is the only place to benefit from RTV. Metal gasket and just enough RTV both sides of gasket. Remember to leave to cure for ten minutes before assembling.
There is a small pipe going from the expansion tank and up and over the cam belt cover. There is a Y junction on it. That plastic connection is an air separator. Maybe that needs replacing. Is the pump working properly? I always fill with the car level.
Remove both plugs on stat housing and rad.
Fill tank until at the top of the rad and fit plug. Then fill tank until at stat housing. Fit plug. Take for a drive. A good drive. Then check and fill the tank to the level. It should be as simple as that.
Only use de-ironised water with coolant. It keeps inside in good condition from corrosion.
If you can hear bubbling when you rev that's a red flag for head gasket depending on if you hear inside or out. Remove expansion tank cap and start engine. Then standing at front rev engine using injection pump linkage while looking in tank. If the reving causes bubbles then head gasket suspect.
Buy a snif test from Amazon to confirm.
These engines are very hardy and nearly all the time it will only fail the head gasket. That said the cylinder head can crack in the exhaust ports but that usually results in leaving a faint trail of steam.
I am more concerned your expansion tank split. This could mean the head gasket has failed from cylinder to water which results in compression entering the coolant and building up pressure which in turn can blow seals. Like P gasket and water pump. And also damaging the expansion tank if the caps pressure release is not working.
Like I said earlier, test the tank for bubbles and do a sniff test.

https://amzn.eu/d/0eoPqgeC

Good luck

Click to expand...

Thanks for the long writeup. Never seen the leak tester you linked to before, looks really neat. Will order one of those to do a test. Will check the air separator also

Been driving the car and keeping an eye on the coolant, after a couple of days driving the air seems to have found its way out from the heater, no more bubbling. And doesn't seem to be loosing any/much coolant, last check in the termostat housing I could maybe top up about 0.5dl of coolant after a couple of days so I guess maybe thats ok because some could find its way out the breeder hose. The heater is blasting out really hot air when turned to max.

I did not flush anything, will need to change the coolant because I have to much water in the mix right now. Doing this I will to a proper flush. I will do a head gasket replacement before the winter, and change the waterpump to a geniune one at the same time. But first I need to go through all the rust to see if chassis and/or body are worth saving.

Even pulled my trailer with a total weight of 3500kg about 200km with no problems, steep up hills it never reached above the top mark on the temperature gauge. Funny that I got revealed to see the temperature gauge go up, because then I knew the sensor was submerged in coolant I will fill up the tank to see how much diesel it consumed on that trip. Think I maybe have a Turbo problem, or something else, because sometimes it felt like the car completely lost all power and was really struggling. But that problem needs to wait.

As a side note I followed this youtube series when I changed P-Gasket and pump

Had no issues luckily.

Thanks for all the help and support!

I’ve driven a 300tdi in Switzerland Alps and Frence Pyrenees on low cooling water at over a 36dgr temperture before I found the problem. Now 10 thousands of miles further stil no problem.

When you replace the P-gasket : clean out the holes where the bolds go in, blow out any cooling water, remove any sealend.

Good it's running better, the 300tdi doesn't always need toppign up. It will find it's own level and stay there. What I mean is, if it drops, keep an eye on it, if it stays there day after day then that's it's preferred level. If it keeps dropping then there is an issue that needs finding.
Temp gauge on a 300 is not accurate.
When it first came out people complained when towing that the gauge went up and down so land rover changed it. It now never moves usually until it's too late. Lesson here is if it goes up to just under red when towing then there is something wrong.
I can tow a horse box with a horse with no problems. It needs checking