Problem solving

[Mikeq1977]

Losing coolant constantly,  ran pressure tests and found no leaks is there anything else it could be rather than head gasket problem? 2008 d4d Luna avensis 

[Byzii]

There's only so many places the coolant can go.

Pressure tests don't always highlight the problem. If you want to be really throrough, you need to do this somewhat methodically. I also had a coolant problem and these steps should help you since I was chasing the problem incorrectly and didn't take controlled measurements to fully understand what was happening.

First, you need to take accurate measurements. Two measurements are required, on a completely cold engine and on a throroughly hot engine. The engine needs to be really up to its full temperature, which means it needs a good highway run (of course, if your coolant loss problem isn't as severe).

Once you have that baseline, you need to understand when the coolant gets lost. When you first start your car from cold, coolant circulates in the "closed" loop - coolant doesn't go through radiator. Coolant starts going through radiator once the thermostat opens, which is around 80 degrees Celsius. From this you can test whether the coolant gets lost even when driving without getting the engine up to temperature, or does coolant get lost only once engine is warmed up? This narrows down the problematic area. (In my case the radiator had a tiny hole at the bottom and would occasionally leak.)

If your coolant gets lost even when it doesn't go through radiator, you can rule that out. If there are no visible coolant stains or pooled up coolant at the bottom plastic pan, then you could look at your waterpump area. It's probably hidden by the timing belt/chain cover, but if you're losing enough coolant, you could probably see coolant stains somewhere on the cover or where the bottom end of the cover meets engine block.

Is there bubbling in the coolant expansion bottle? Is there any discoloration in the bottle? Oil in there? Also, take the engine oil filler cap and have a look around, if you've been losing coolant long enough and it gets into the engine, oil will be like a milkshake.

Another area of concern could be the cabin heater core. You can have a look around there, maybe the carpet is wet underneath?

[Heidfirst]

Hi Michael, welcome to TOC 🙂

2.0 or 2.2 D4D?

[Mikeq1977]

1 hour ago, Heidfirst said:

Hi Michael, welcome to TOC 🙂

2.0 or 2.2 D4D?

2.0

[Mikeq1977]

Just now, Mikeq1977 said:

2.0

 

1 hour ago, Byzii said:

There's only so many places the coolant can go.

Pressure tests don't always highlight the problem. If you want to be really throrough, you need to do this somewhat methodically. I also had a coolant problem and these steps should help you since I was chasing the problem incorrectly and didn't take controlled measurements to fully understand what was happening.

First, you need to take accurate measurements. Two measurements are required, on a completely cold engine and on a throroughly hot engine. The engine needs to be really up to its full temperature, which means it needs a good highway run (of course, if your coolant loss problem isn't as severe).

Once you have that baseline, you need to understand when the coolant gets lost. When you first start your car from cold, coolant circulates in the "closed" loop - coolant doesn't go through radiator. Coolant starts going through radiator once the thermostat opens, which is around 80 degrees Celsius. From this you can test whether the coolant gets lost even when driving without getting the engine up to temperature, or does coolant get lost only once engine is warmed up? This narrows down the problematic area. (In my case the radiator had a tiny hole at the bottom and would occasionally leak.)

If your coolant gets lost even when it doesn't go through radiator, you can rule that out. If there are no visible coolant stains or pooled up coolant at the bottom plastic pan, then you could look at your waterpump area. It's probably hidden by the timing belt/chain cover, but if you're losing enough coolant, you could probably see coolant stains somewhere on the cover or where the bottom end of the cover meets engine block.

Is there bubbling in the coolant expansion bottle? Is there any discoloration in the bottle? Oil in there? Also, take the engine oil filler cap and have a look around, if you've been losing coolant long enough and it gets into the engine, oil will be like a milkshake.

Another area of concern could be the cabin heater core. You can have a look around there, maybe the carpet is wet underneath?

No bubbling no discoloration oil is good and no dampness anywhere

[Mikeq1977]

Thanks for reply s by the way

[Heidfirst]

2.0 1AD not immune to head/head gasket issues but anecdotally at least appears much, much reduced risk from 2.2 2AD.

[Mikeq1977]

Had two local mechanics look at it and both said trouble inside engine but would it be worth it to bring it to main dealer to try diagnose it or am I just wasting money?

[Byzii]

I'd say dealers are last resort and are always bad at diagnosing things. They'll hear you say "losing coolant" and they won't even allow you to finish your sentence, they'll just give you a price of 7k pounds for a new engine.

You need a reputable mechanic that is qualified and willing to diagnose and possibly fix it or at least advise you, not just some garage that wants your money and couldn't care less about you or your business.

[Mikeq1977]

7 minutes ago, Byzii said:

I'd say dealers are last resort and are always bad at diagnosing things. They'll hear you say "losing coolant" and they won't even allow you to finish your sentence, they'll just give you a price of 7k pounds for a new engine.

You need a reputable mechanic that is qualified and willing to diagnose and possibly fix it or at least advise you, not just some garage that wants your money and couldn't care less about you or your business.

Exactly what I thought I'll have to investigate more

[avetoy]

Local Toyota repair man said to me: if coolant expansion tank is black inside, then there is head gasket leaking. 

One possibility to leak is that extra heater (webasto). If you have it in your car...

[Mikeq1977]

18 minutes ago, Byzii said:

I'd say dealers are last resort and are always bad at diagnosing things. They'll hear you say "losing coolant" and they won't even allow you to finish your sentence, they'll just give you a price of 7k pounds for a new engine.

You need a reputable mechanic that is qualified and willing to diagnose and possibly fix it or at least advise you, not just some garage that wants your money and couldn't care less about you or your business.

 

1 minute ago, avetoy said:

Local Toyota repair man said to me: if coolant expansion tank is black inside, then there is head gasket leaking. 

One possibility to leak is that extra heater (webasto). If you have it in your car...

👍

[Heidfirst]

14 hours ago, Mikeq1977 said:

Had two local mechanics look at it and both said trouble inside engine but would it be worth it to bring it to main dealer to try diagnose it or am I just wasting money?

have you had a sniff test done?

[Mikeq1977]

21 minutes ago, Byzii said:

I'd say dealers are last resort and are always bad at diagnosing things. They'll hear you say "losing coolant" and they won't even allow you to finish your sentence, they'll just give you a price of 7k pounds for a new engine.

You need a reputable mechanic that is qualified and willing to diagnose and possibly fix it or at least advise you, not just some garage that wants your money and couldn't care less about you or your business.

 

5 minutes ago, avetoy said:

Local Toyota repair man said to me: if coolant expansion tank is black inside, then there is head gasket leaking. 

One possibility to leak is that extra heater (webasto). If you have it in your car...

👍When you say webasto do you mean air con?

[Mikeq1977]

2 minutes ago, Heidfirst said:

have you had a sniff test done?

Sniff test?

[avetoy]

Webasto is general name to me for extra heater that uses car fuel... This heater is handy when weather is freezing. Warms engine up faster.

It heats the coolant and inside the heater are some o-rings which may leak. Repair man told that too...

[Heidfirst]

2 hours ago, Mikeq1977 said:

Sniff test?

e.g. https://www.sealey.co.uk/product/5637204645/combustion-leak-detector

[Mikeq1977]

👍

[Taxi501]

I bought a new avensis 2.0d in 1998 , by the time I’d done 30,000 miles I was back to the garage numerous times complaining about it using coolant, they couldn’t find any problem or leaks.

I found the leak myself by chance, when the engine was fully warmed up a tiny pinhole appeared in the top hose, it was spraying coolant into the foam panel under the bonnet. As the car was a taxi, my best guess is it was always hot so the leaked coolant dried into the foam as I was driving