Overheating

m4rkw · July 20, 2021

18 minutes ago, rich1068 said:

Put the torch hard up to one side of the tank and look through the tank from the other side. Nudge the car as you're doing it and ideally you should see the pink coolant moving.

I tried, nothing. I think there’s none there

m4rkw · July 21, 2021

Got some coolant from Toyota, topped it up. It wasn't extremely low, as soon as I started pouring it is I could see it at the bottom of the expansion tank, so the level was just underneath where that starts. Booked in for checks on Monday.

true blue · July 21, 2021

Wise decision for peace of mind especially as summer has arrived with a vengeance I expected. more postings on air con problems !!

Dave

m4rkw · July 21, 2021

So I topped it up at lunchtime to just under the full level, left it until just now, checked again - still at the full level, no marks on the ground. Drove it for about 15mins a mile down the road and back. Checked it idling with the AC on, didn't seem to be overheating. The coolant level has dropped by about 1cm from where it was though - is that likely just because it's hot or could it indicate the coolant going somewhere? I'll check again later when it's cooled down.

m4rkw · July 21, 2021

After cooling down it’s low again, once again below the visible area on the expansion tank. Seems like it’s losing coolant fairly quickly but still nothing visible on the ground or anywhere ai can see in the engine bay. Gonna avoid driving it until I can take it to the garage.

rich1068 · July 22, 2021

Very odd for there to be no signs whatsoever. How much would you say you've put in altogether?

m4rkw · July 22, 2021

I actually didn’t realise i also needed to fill the radiator through the radiator cap, started filling that this morning and that took a fair bit too. I reckon i’ve added maybe a litre so far.

ColinBarber · July 22, 2021

4 hours ago, m4rkw said:

I actually didn’t realise i also needed to fill the radiator through the radiator cap, started filling that this morning and that took a fair bit too. I reckon i’ve added maybe a litre so far.

Yeah you need the main system full before measuring the drop otherwise anything you put in the expansion bottle will just be used to fill up the system. If your top hose wasn't full then you have lost quite a lot of coolant so that all needs to be replaced, then you can see how quickly it is being lost.

m4rkw · July 22, 2021

1 hour ago, ColinBarber said:

Yeah you need the main system full before measuring the drop otherwise anything you put in the expansion bottle will just be used to fill up the system. If your top hose wasn't full then you have lost quite a lot of coolant so that all needs to be replaced, then you can see how quickly it is being lost.

Yeah, I filled up the radiator and took it for a quick drive, not very far at all. Came back, expansion tank level looks about the time. Will check it again tomorrow.

It's all fairly academic at this point as there's very likely a leak somewhere so it's going to the garage on monday, but will still be interesting to see just how quickly it's leaking. Apparently there are a couple of places where it can leak without pooling on the ground.

m4rkw · July 23, 2021

The loss isn't as dramatic as first thought. After my quick drive yesterday it was still basically full, barely took another half a cup this morning.

m4rkw · July 23, 2021

Does anyone know how the temperature gauge is calibrated, i.e. what temperatures the notches on it equate to? I know the middle is the normal operating range, and it's probably a range rather than a specific temp. Just trying to figure out what the potential impact is of getting up to the notch before the top. Since there was no check engine light and the car seems to be running fine I'm hoping I got away with it but still curious to know what the calibration is.

ColinBarber · July 24, 2021

16 hours ago, m4rkw said:

Just trying to figure out what the potential impact is of getting up to the notch before the top.

Zero impact, you have nothing to worry about. You don't get engine damage unless you notice a loss of power and/or pinking and you continue to drive for several minutes in that state. That situation doesn't occur unless the temp gauge is off the scale.

m4rkw · July 24, 2021

3 hours ago, ColinBarber said:

Zero impact, you have nothing to worry about. You don't get engine damage unless you notice a loss of power and/or pinking and you continue to drive for several minutes in that state. That situation doesn't occur unless the temp gauge is off the scale.

That is good news - thankyou. Someone else suggested changing the transmission fluid and oil pre-emptively just on the offchance they got a bit hot, what do you think? Both are fairly fresh, transmission was done last year and the oil about 1000 miles ago. I don't think it was hot for very long so I'm leaning towards just leaving those but.. not sure.

ColinBarber · July 24, 2021

No reason to do the transmission fluid, it is self-contained with its own cooler - it doesn't even have the cooler inside the radiator like on some other Toyota/Lexus vehicles. Therefore its temperature wouldn't have increased because the engine was hot. The transmission also has the capacity to tow a trailer so it has plenty of tolerance and cooling capacity. If the fluid is black (rather than dark brown which is tends to go) and smells burnt then it should be changed.

As for the engine oil then if it was a good quality synthetic oil it would easily cope with a slightly higher temperature. Personally I wouldn't change it but you seem particularly concerned and it is an easy thing to do so you may want to go ahead.

m4rkw · July 24, 2021

2 hours ago, ColinBarber said:

No reason to do the transmission fluid, it is self-contained with its own cooler - it doesn't even have the cooler inside the radiator like on some other Toyota/Lexus vehicles. Therefore its temperature wouldn't have increased because the engine was hot. The transmission also has the capacity to tow a trailer so it has plenty of tolerance and cooling capacity. If the fluid is black (rather than dark brown which is tends to go) and smells burnt then it should be changed.

I'm not sure there's a transmission cooler on mine, haven't seen one anyway. It's a Harrier, so not allowed to tow with it because there's no weight specification on the V5 or the vin plate. I'll check the fluid though.

ColinBarber · July 25, 2021

13 hours ago, m4rkw said:

I'm not sure there's a transmission cooler on mine, haven't seen one anyway. It's a Harrier, so not allowed to tow with it because there's no weight specification on the V5 or the vin plate. I'll check the fluid though.

I've assumed you have a UK supplied vehicle which all have the transmission cooler. Harriers don't unless they had towing pack installed, but in any case the transmission wouldn't have been overheated because the engine was running hot.

m4rkw · July 26, 2021

Curious. The garage tested it for a few hours, can't find any sign of a leak.

rich1068 · July 26, 2021

I've a feeling it may have been getting low, the hot weather has done for what you had left in (diluted coolant maybe?) and you needed more or less a complete refill. Topping up into the expansion tank was just going to the rest of the system.

Just one of those things possibly?

m4rkw · July 26, 2021

52 minutes ago, rich1068 said:

I've a feeling it may have been getting low, the hot weather has done for what you had left in (diluted coolant maybe?) and you needed more or less a complete refill. Topping up into the expansion tank was just going to the rest of the system.

Just one of those things possibly?

I've never had to put coolant in before, in 3.5 years of owning the car. Coolant was changed by the garage 3 months ago, then suddenly over a litre was missing. It had to go somewhere.

m4rkw · July 28, 2021

New plan: I'm going to change the radiator cap and keep an eye on it. If it still loses coolant I'll take it to a specialist.

Comfo · July 29, 2021

I've followed the question from m4rkw and the feedback from NemesisUK, ColinBarber & rich1068. I have a Lexus RX 300 SE, 2005 LPG which is also overheating. I have broken down four times in approximately 12 months. I've parked her up with the expectation of replacing the engine due to a suspected head gasket, which I've been advised would require a replacement engine as the garage I use wouldn't bother replacing or skimming the engine head and new parts etc. Anyway, I've ordered the pink coolant today, to monitor where the leaks are coming from with a view to saving my car as it is incredibly reliable and efficient, but for this unknown issue. I'm reluctant to sell her, but I will if required. The garage I use kept asking me to monitor the amount of coolant which I did. The breakdown recovery mechanic said the same, but eerily none of them ever mentioned the head gasket which I found extremely odd. What are your thoughts other than what you've stated to m4rkw?

m4rkw · July 29, 2021

A hydrocarbon test would confirm head gasket diagnosis.

Herbie · July 29, 2021

1 hour ago, Comfo said:

I've followed the question from m4rkw and the feedback from NemesisUK, ColinBarber & rich1068. I have a Lexus RX 300 SE, 2005 LPG

Hope it's not my old RX - GY05 HVK?

Herbie · July 29, 2021

6 hours ago, m4rkw said:

A hydrocarbon test would confirm head gasket diagnosis.

Agreed.

Also Antonio, if you take the oil filler cap off, does it look a bit like mayonnaise? That can happen with head gasket failure although not exclusively. Mayo can also be due to condensation if the car olny does short trips and temps are low.