Coolant Leak & Misting Up

sc008y · February 23, 2014

Hi guys.

I've had the 200 back on the road for 3 weeks now without a major snag until last Thursday.

While driving home from work, the oil light came on, so I stopped at a garage and checked it. Nothing too major, so I decided to wait until I got home, let the thing cool down, then top up. No snags.

While in there, I spotted the coolant level was a bit low, so I topped up the expansion tank. Again, no immediate problems.

I'd almost gotten home (having driven about 50 miles since stopping) when suddenly the screen misted up and I could smell warm, wet rubber. Turning up the heat only made things worse, but aircon on full cold cleared it. I was only a mile or so from home so decided to keep going and inspect it during daylight.

Following day, I checked the fluid and it was low, so topped it up by parking uphill, and filling the rad until it overflowed. Left it running for a while and nothing untowards happened. As I'm new to Lexus, I put it down to a Lexus '-ism'.

Just driven it now and as I started it up, there was a sloshing type sound. After a minute or two that stopped, so I figured maybe there was some air in the system and it had cleared itself, but after about 5 minutes driving the car misted up again, plus the check engine light is now flashing.

I've looked and can't see any obvious leakage, but there's nothing left in the expansion tank.

Any ideas where the fluid could be going?

steve2006 · February 23, 2014

Regarding the Check engine light I would perform a code read and post back what flags up,it could be that the engine overheated and the oil light came on indicating an abnomal oil temperature.

Did you see any increase on the temperature gauge?

Regarding the cooling system problem it would suggest a leak on the system considering the water loss and I would be looking at the heater matrix for the possible source of the leak given the misting up of the screen excacerbated by turning up the heater controls.

Was the windscreen misting accompanied by a sweet smell associated with antifreeze?

sc008y · February 23, 2014

No rises in temp.

The oil level was a bit low, not below the min mark, but low, so I put the light down to that.

Yes, there was a sweet smell.

If the leak is in the heater matrix, will keeping the temp set to cold minimise fluid loss?

Where is the heater matrix located?

As for a code read, I've not got the kit to do so.

Jonesy200 · February 24, 2014

The sloshing sound is usually air trapped in the matrix. If the heater matrix is leaking unfortunatly its a dash out job the heater matricx is the 2 pipes sticking out just tothe right of the brake servo. Like i said its dash out job. I'm not big on the coolant additives like k seal etc but maybe try 1 and see if that cures it?

sc008y · March 6, 2014

Sorry for the extremely long time it has taken me to reply, but I blocked the site for some reason. Back now though!!

Leak was defo in the heater matrix as I've isolated it (by re-routing the pipework leadinginto the cabin back onto itself!)

Hey presto, no more leak, or heating :(

Sadly, the CEL and TRC OFF lights are now flashing at me all the time, and the car sounds like it's misfiring.

I read somewhere on the site where someone cleaned the MAF to solve this problem, although I'm not sure how the MAF could influence the TRC, but it is wiggly-amps after all!!

I have recently changed the air filter from a really crudded up one, so maybe I need to look at this. Question: Where is it, and anyone have photos?

I would pull the codes, but I work from 0600 to 1730 every day so don't get chance to get to a garage very often, and don't have the necessary kit myself.

There was a write-up frm the person, but they had an after market air filter, which I don't.

Thanks again guys.

sc008y · March 6, 2014

sorry, forgot to mention, I did try the Radweld type 'fix', but it didn't work.

Maybe a different brand would have worked, but I doubt it, the speed it was leaking out.

Jonesy200 · March 6, 2014

The air filter is a 2 min job see pic just undo the 2 clips circled and pull out and the rest is self explanatory lol. They do k&n's on eBay for around 30 to.

Jonesy200 · March 6, 2014

Take a look at this thread. http://www.lexusownersclub.co.uk/forum/topic/64252-how-to-change-your-heater-matrix/

Jonesy200 · March 6, 2014

Apparently you dont need to take the dash out so my bad if that thread and instructions work for you. good luck mate let us know how it goes.

Kev B · March 6, 2014

Hi Kevin.

Sorry to hear that you're having problems.

Looks like you're on the right track now though thanks to other members.

K Seal and other brands will probably not help in any way and the fact that the weather is going to get warmer means that you will no doubt have time to save some money to put aside for the Heater Matrix fix.

Good luck and keep us posted.

Mordajedna · May 23, 2014

Engine misfire after your heater core got f**ed you probably got air pockets in the engine. Get a coke bottle, fill it up with water wrap its thread in rubber glove- makes a nice seal- open your radiator cap turn on engine. Fit the bottle neck into radiator and observe bubbles..when they re gone your engine should work ok.

If it keeps spitting coolant from expansion tank and you keep getting misfore- get compression test it mght be HGF as it was in my case.