Yes, I have done a search here, too. I've been a bit of a long time lerker!
Car is a 1992 LS400 141k miles (today!)
Here's the story
Symptoms of overheating first came about around 2 or more months ago. 35 mile trip down the A roads to Priddy, Somerset via Cheddar Gorge. Coolish day, damp and some heavy rain. Climbing up the Gorge - it is twisty and steep in some parts, got stuck behind a van that was struggling, slow around 10mph, and those tight bends. Temperature Gauge shot up to H. Once on the flat the gauge quickly returned to its normal reading. Trip back home was uneventful. Topped up the coolant, which was low. I regularly and frequently check levels, BTW. Thought nothing more of it.
3 weeks ago trip 8 mile trip down to the City Centre - really a clear run along country lanes and a dual carriageway - about 3 miles into the journey. Gauge shoots up to H, and stays there or there abouts until I pull in, when it drops rapidly to normal. Again, journey home uneventful.
Intalled a new thremostat, after all it cannot do any harm anyway, and the symptoms above seemed to suggest this. Did this Tuesday last. Have been driving to work and back a 10 mile journey everyday - sometimes twice - no issues.
So to today.
Bristol to Bampton - around 75 miles there and 75 back, mostly M5. I am not heavy right-footed and usually cruise around 65-70 mph (The Lexus is that sort of drive for me !)
No problem for 55 miles, then stop/slow in traffic very briefly for no more than 3 minutes - really crawling as drivers on our carriageway were rubbernecking an over-turned caravan on the other. Gauge went up to H and stayed there.
Pulled in when it was obvious it was not going to fall back - as it had done in every instance. Let the car cool down. Very little water - here's the thing although I have been replenishing coolant/water - I have never seen the car, or had evidence of the car physically dumping loosing coolant (ie a puddle).
There was steam coming from the Top Left Hand cylinder bank, not in great amounts, but escaping nonetheless. Waited for the car to cool down a little then replenished with water, with the car running, for around 10 minutes until the level stayed constant.
The car - when started from hot always has a tendency to badly misfire and almost stall in summer weather - and did so again at this time. Would a gone head gasket and escaping electrics affect HT leads and plugs (Sorry - I am new to Lexus, being familiar with Saabs).
2 mile drive to my daughters - no issues. Checked coolant - it was as was. A bit of a rattle from the front of the car, which soon disappeared. I know these things do not disappear never to come back again, and having listened to the idler pulley with a screwdriver, which appears to be the culprit)
Time to drive back to Bristol. Double check coolant. Fine. 8 miles into the drive - country lanes gauge climbs back to H for around 2 minutes, and then drops down rapidly - as it does - to its normal reading. The rest of the journey 60-odd miles along the M5 home was uneventful. I haven't checked to see if there is a pool yet, or if the coolant has all but disappeared again, but neither would surprise me.
What is making me rather suspicious that something went on with the car before I bought it, and I suspect before the person I bought it from, (he is a good and very trustworthy friend) as the low coolant light never shows on the dashboard, as a warning except at start-up - so I wonder why this has been disconnected?????
Is there a way of servicing the switch in the expansion tank - it seems a sealed unit to me?
So, what is the concensus?
- Water Pump (How long do they last)?
- Head Gasket - Left Hand Bank?
- Failed Hose - which one's the favourite?
- Radiator Flush (on my list to do's in anycase)?
And of course, where has the water gone?
Any help, wise words of wisdom or experience will be gratefully appreciated, and please pose further questions that I can answer to help find a resolution.
I am here to learn more about myLexus, as Workshop Manuals apart from pirated ones are few and far between, here! We all have to start somewhere!