Blown head gasket
#1
Instructor
Thread Starter
Blown head gasket
I suspected my engine had a problem. It consumed the all the coolant from the reservoir in about 400 miles. On startup I could smell burning coolant for a split second from the exhaust (coolant in the combustion chamber). After shut down the cooling system was over pressurized (exhaust in the cooling system). The final straw was crud forming on the inside of the oil filler cap. So this is where I'm at now
Heads are at the machine shop getting milled. I bought a Lexus "valve grind kit" so I would have all new oem gaskets.
Heads are at the machine shop getting milled. I bought a Lexus "valve grind kit" so I would have all new oem gaskets.
Last edited by 911LE; 02-23-16 at 04:55 PM.
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CamelKool (07-15-20)
#2
This is the first post ive seen with a blown head gasket on one of these engines.
Did the car overheat at all before the gasket failed from a bad thermostat, radiator etc?
How many miles on the car?
Did the car overheat at all before the gasket failed from a bad thermostat, radiator etc?
How many miles on the car?
#3
Instructor
Thread Starter
The car has 110k miles. I haven't owned it very long. I went to do the timing belt service and noticed two things. First was the radiator cap spring was broken so the cooling system never pressurised. Second was a large amount of dried coolant droplets everywhere in the engine compartment (only visible when all the covers were removed). It ran fine and never overheated on me. I've owned a lot of Toyota pickups over the years so I know the symptoms of a blown head gasket.
#4
Looks like a major surgery for a relatively low mileage engine. Did you measure the head gasket surface run-out on the engine block and on the head blocks to see if they are off specs?
#6
Lead Lap
The car has 110k miles. I haven't owned it very long. I went to do the timing belt service and noticed two things. First was the radiator cap spring was broken so the cooling system never pressurised. Second was a large amount of dried coolant droplets everywhere in the engine compartment (only visible when all the covers were removed). It ran fine and never overheated on me. I've owned a lot of Toyota pickups over the years so I know the symptoms of a blown head gasket.
#7
Instructor
Thread Starter
I haven't checked the block deck surface for warpage yet. This weeks plan is to clean the deck and piston tops and check for cracks. I did not see any conclusive evidence of where the gasket failed. All 8 combustion chambers looked identical as did the spark plugs. Usually it's pretty obvious which cylinder(s) are affected but I did catch it really early. I know my engine is low mileage but it's not nearly as clean internally as I expected it to be. The piston tops and chambers are covered in deposits that are quite thick in spots. The intake ports are covered in a thick, sticky black oily residue and the intake manifold had a few tablespoons of oil in it.
On the positive side the cross-hatching in the liners looks factory new and there was only a very small amount of sludge in one of the valve covers.
I realise that this is major surgery but aside from the time involved the cost is low. The gasket kit was less than $300 and has everything I need and more. I did get new factory head bolts even though the fsm says they are reusable if they meet specs. This car is not my dd so I'm not rushed doing the work. I actually enjoy working on it sometimes.
On the positive side the cross-hatching in the liners looks factory new and there was only a very small amount of sludge in one of the valve covers.
I realise that this is major surgery but aside from the time involved the cost is low. The gasket kit was less than $300 and has everything I need and more. I did get new factory head bolts even though the fsm says they are reusable if they meet specs. This car is not my dd so I'm not rushed doing the work. I actually enjoy working on it sometimes.
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#9
Instructor
Thread Starter
I thought about it but I want to make sure my engine is 100% before I spend any more. Pulling the intake wasn't very hard so if I need to I could do it again fairly quickly. The hardest part was disconnecting all the connectors. My finger tips hurt for a few days after!
#13
Thats suprising to hear the engine had thick deposits and sludge in the intake. I thought these were pretty clean running engines especially with only 100k on the engine. Did you have any maintenance records on the car from lexus or prior owner?
Sounds like lack of oil changes, cheap gas etc
Sounds like lack of oil changes, cheap gas etc
#14
Lexus Test Driver
you blew up an Lexus Ls?????!! that's like, impossible. howd you manage to pull that off? that takes work and serious effort, like you actually really want to blow it up. that's so hard to do it almost deserves an award.
nice starter btw. I hate seeing those. I had the unfortunate experience of holding my starter in my hand. that's the one part that all LS owners should never have to see
nice starter btw. I hate seeing those. I had the unfortunate experience of holding my starter in my hand. that's the one part that all LS owners should never have to see
#15
Instructor
Thread Starter
I didn't exactly blow it up. I caught it before it ran rough, threw codes, etc. I have records from lexus up to 60k then the po had records from then on. The machine shop concurs on the cheap gas being used. I've only put about 600 miles on the car after buying it. I did the timing belt, idlers, and water pump about 400 miles ago. I watch my vehicles fluid levels like a hawk. That's how I spotted the coolant usage. I'm going to clean everything really well and run good gas and Mobil 1 from here on out.