Hi Everyone

This is my very first thread and I’m a novice, I’m not a mechanic so please bare with me…

I have a 2006 Lexus RX 350. I purchased it about 7-8 months ago and it didn’t have any service history. I paid £3,000 and mileage was 120,000 miles. Initially the car was fine, no issues.

Over the past 6 weeks during winter, as the temperature has gotten really cold I noticed that the engine was taking a while to heat up and that my heating was not working properly. It would take about 20-30 mins for engine to heat up and for heating to work properly. The heating would blow cold air when idling and warm air when driving. Some times the engine temperate needle would go slightly over half way before coming back down to the middle.

Initially I thought it might be thermostat but I took it to a ‘back street’ garage who noticed that the coolant levels were low. After topping up with water and feeling the hoses he said the hot water is flowing but the radiator was not getting hot. He did a bit of a coolant flush by opening the valve and constantly pouring water for about 10-15 mins. Still nothing. He said my radiator was blocked and needed replacing. He also said it appeared as though someone may have used K Seal or similar in the past to fix a leak maybe. The coolant that came out was really dark brown and the inside of the cap had dark specs. Radiator still didn’t warm up.

Not sure what to think about radiator being blocked but anyway…

While waiting for replacement radiator the issue improved slightly probably because of his Micky mouse coolant ‘flush’.

Went back to have the radiator fitted, I read that it takes 8.4 litres of coolant but they only used 5 litres so I can only assume they never bled it properly. (I know there’s two places to drain from, they probably only did one)

Now the engine warms up quicker and heating heats up quicker too but the passenger side heating is warm compared to drivers side which is hot. This wasn’t an issue before. Same with the rear vents, only warm.

I read the thread about the servo and don’t think it’s that as can’t hear any clicking. Could it’s be the heater core needs to be flushed? Or they nicked a hose or clip during the radiator replacement?

One other issue is that I get insane amounts of condensation building up on the inside is the windscreen. I haven’t really noticed any water ingress, could it be linked to clogged drains as there’s no fresh air flow?

Any advice would be greatly appreciated.

Many thanks

 

The condensation inside the car is the thing you should be most concerned with. Does the inside of the car smell like coolant? You can't get all of the coolant out since some is in the engine and heater core the amount added sounds about right. It's possible the air was not properly bled out of the system if there are not leaks and the radiator cap is working properly then generally this resolves itself.

Condensation could be because of a clogged A/C drain is the passenger side carpet wet? Does the temperature gauge read normally?

I really hate stop leak products some of them coagulate into chunks and are very hard to remove.

 

Replace thermostat (to warm up faster) and water pump (to have hot air while idling) first. Use OEM (so you will not return to them in future).
PS: 1) If radiator was blocked then you would have an overheating problem, but you have the opposite one. 2) Low level can cause "cold air" while idling.

 

PPS: Did you check temp settings of dual-zone climate control? Maybe the passenger side is set to be "warmer"?

 

Thanks for the quick replies.

I assumed it may have been the thermostat but mechanic said because he could feel the hoses to/from the radiator getting hot, it’s he ruled out the thermostat. He kept feeling the rad and saying it was cold, not heating up but that hot coolant was flowing through hoses.

also since changing the rad, the engine and heating heat up to temp much quicker now so I think this has resolved the problem, yet created another, haha.

As for leaks and smells, I haven’t noticed any leaks or puddles within the car nor have I noticed any coolant smell.

What does sound plausible is that you mentioned the system wasn’t bled properly…?? Before replacing the rad, both driver and passenger side heated evenly (albeit took a good while to heat up).

Do I go back to the mechanic and ask him to try bleeding the coolant/rad a bit more?

Is this something I can do by running the engine, opening the coolant cap and waiting to see if any more air bubbles come out? Can I squeeze some hoses to try and force this?

As for the condensation, this is a major problem atm which I’m clueless on. 🙁

Thanks again for your replies, it’s much appreciated.

 

Yes I did check this. Both temps set the same but noticeable difference.

it worked as normal before changing the radiator and coolant, even though it took forever to heat up. It’s definitely something to do with the rad/coolant replacement.

I have to set the passenger side to high for it reach the same temp as 26 degrees on drivers side. Weird.

 

I know Thermostats can be common to replace but when I went to enquire with Lexus, was told they don’t usually need replacing on RX…?? 🤷🏻‍♂️

As for the overheating, I noticed a few times that the engine temperature gauge did go over the normal half way mark a few times but then came back to normal.

In the past when I’ve had thermostat issues on my previous Lexus IS200, I’ve watched the needle bounce around.

I did read up somewhere that rust and sludge can develop within the radiator causing it to get blocked. When the mechanic did an initial partial flush when diagnosing the problem, saw lots of dark brown water come out. This could either have been K Seal or rust, so it does kind of make sense although I would never have guessed it to be the radiator.

As mentioned, now heating comes on straight away and engine gets to temp much much faster than before.

Just need to sort out the passenger climate control and identify cause of the major condensation on windscreen.

Thanks again for the help guys. I hate cars 🙁 haha

 

Thanks for the reply.

so the work was carried out yesterday 21/01/22. Today I’lol be travelling on the motorway, distance of around 100 miles each way so I’m hoping that this blast should help resolve the issue itself.

No haven’t visually noticed any water on passenger side mats but from now on I’ll start touching them every morning to confirm this.

Drain could definitely be clogged. Now this I think I can do myself haha. So I know there’s 2 drains in the sun roof, I’ll test these to see. Are there any other drains I can check? You said A/C drain??

Temp gauge does read correctly

 

Guys..!!!

The entire left side of the car floor is absolutely soaked, front and rear passenger. Mats are drenched 😰

I'm guessing this could be an issue with clogged drains or dislodged drains within the pillars…??

could anyone confirm this diagnosis and suggest if there are any other drains apart from the two I know of in the sunroof?

Thanks

 

So this morning noticed a massive puddle on the road under the car. Took it back to mechanic who said that the pressure from the new coolant must have blown the water pump.

The water pump is leaking and has play in it. The metal water inlet pipe and housing block is also leaking and this appears so have been patched up previously.

Rang Lexus for parts:

water pump, thermostats (just to be safe), water pipe and housing. £430 inc vat. Not got a price for labour yet but don’t expect it to be less than £1000.

Tried 3 private garages, no mechanic will touch it.

Now im asking myself do I spend £1500 trying to repair it to keep or do I try cut my losses and sell for whatever I can get which won’t be much…

💔😰😱

 

If the sunroof drains are clogged very likely you will see staining on the headliner do you have this? Aisin water pump is about £115 on Ebay what exactly is the pipe and housing you were quoted? The labour you are estimating is much much higher than it should be.

See this diagram
https://www.japan-parts.eu/lexus/eu/...water-outlet/2

 

Thanks for this, the diagram was really helpful.

Can’t see any staining on headliner.

Please see picture attached for the parts that are leaking in addition to water pump.

 

sticking with sweet smell - coolant leak, otherwise - wet carpet (water)

 

PS:
Here is the problem:

 

It’s water, just need to identify where it’s coming from, guessing it’s clogged or dislodged sunroof drains…?

it’s the entire front and rear passenger side.