caliLS400

This morning on my way to work, I am cruising @ 75 MPH down the highway. When the I glance @ the temp needle and it's pegged, past the red line.

This happened quickly because after owning a Acura Legend, I take coolant temperature seriously, so I am always looking. As I start to pull over, PPPPSSSSHHHH coolant and steam come out from the gap between the hood and the left fender and underneath the left fender.

Immediatly the temperature went down, I pop the hood and coolant is everywhere but I can't tell where it's coming from. Obviously the level was low, so I refilled it, I always keep a full bottle of coolant in the trunk. I let the car cool, refilled the reservoir waited to see if it would run out somewhere. It stayed. I checked the top level hose and it was hot, this usually means coolant is flowing.

This happened to me last year around the same time, but it was the radiator that had a hairline crack and was also plugged, I had it cleaned and repaired, and replaced the thermostat, it was all good after that.

A few days ago, I noticed the temp fluctuating, going all the way up the H and then dropping back down. When I got home, I immmediately drained the system, flushed it and refilled with fresh coolant, for the last two days it has been fine until today.

Now when I start the car I have this nasty misfiring, and when I finally got to work the engine steamed stinky *** for about 10 minutes, not to mention a strange rattle that's intermittent when I hit the throttle.

Oh and now the check engine light is on too, I pulled codes 21, 41 and 71, which are open and short in main heated O2 sensor, open or short in throttle position sensor, and EGR malfunction.

I can't really tell if there is any coolant in the oil because I just changed it the day before with fresh synthetic and it's pretty damn clean. There is no steam coming from the tailpipes either.

The rough idle and missing sound at start when it was hot, not when it has cooled has me worried about a BHG.

lowKut

iTrader: (3)

My temp gauge fluctuate quite often as well, but the car never over heat (knock on wood). I was told that is could be the thermostat is stuck open.

Sorry couldn't offer any help to you as i am in need myself.

rburg

Had an overheating problem with my 95 LS. Turned out that at one point in it's life the water pump was replaced. There were no leaks so I thought it was my thermostat sticking. My Lexus tech said he knew what it was without even looking at it. I said ok, what is it? He pulled it into his garage and pulled a small hose from the engine that goes to the overflow tank. Blew through the hose with low pressure compressed air and viola! A chunk of black RTV came floating to the top of the tank. He said this is a common problem that many Lexus techs overlook. Since then I've had him replace the water pump and the timing belt and flush the cooling system. Be judicious about applying too much RTV when replacing any part because when the parts are bolted back together the RTV will squish (technical term) out and eventually will come off inside, especially any part that has liquid flowing past/through it. Hope this helps.

avalon42

iTrader: (1)

+1. When I undid my banjo bolt from the radiator top, I noticed this as well. I blew out a considerable chunk of leftover RTV crap from the coolant return line.

JBrewster

Wow, exact same thing happened to me a couple years ago. Had no idea it was anything more than an isolated case.