kvshadow7

Hello. I have a 2007 Lexus IS350 and was driving on the highway where I noticed that the temp gauge is near the H zone. I pulled over and saw that the radiator cap was loose and coolant spilled out. After waiting for the engine to cool down, I put the radiator cap on and tightened it, and drove the car for ~20 miles. I noticed that the temperature was near the H zone again and heard a gurgling sound from the engine, so I pulled over and turned the car off. I could see the radiator fans spinning, but the temperature wasn't going down. At this moment, the car wouldn't start at all! I towed the vehicle to the nearest dealer, and they said it's a blown head gasket after a quick inspection! They're asking ~$6K to replace the head gasket, and I'm not sure if I should do it or replace the engine with a used one in a repair shop. For background, I got this car used just a couple of months ago at ~135K miles with only one previous owner who took excellent care of the car. I already changed the alternator as it wasn't generating enough voltage to charge the battery. The heater was blowing cold air in the past week while idling or behind stoplights. However, I don't think it overheated in the past week, nor did I observe white smoke from the tailpipe. I suspect the water pump wasn't working well, and the fact that the radiator cap wasn't tight exacerbated the issue, which caused overheating. But I don't get why this happened again after I tightened the rad cap. Also, in the past month, I saw that I was getting 13-14 MPG in the city, and I don't drive hard! Before driving I checked the dipstick and I don't believe it had a milky chocolate color. I'm new to the community and would appreciate any suggestions!

LeX2K

What is the coolant level? Since you had little or no heat that likely means the engine was low on coolant and eventually caused your severe overheating. Did the dealer do any tests to confirm the head gaskets are blown or just say they are? Either way doesn't sound good you probably need a replacement engine.

ponteley

~$6K to replace the head gasket..... , - a bit much...
~$6K to swap the whole engine with good, lower miles used one...., - maybe...

Gville350

iTrader: (10)

I would get a second opinion before trashing the car or spending thousands for a repair.

The comments about having no heat only at stop lights or when stopped sound like when I had a pinhole leak in one of my previous car's radiator causing an unpressurized system. Could be your water pump was leaking or not operating normally. TOTALLY normal unfortunately with these 2ISs. This COULD lead to a blown HG. Was the overflow tank empty or full to the top of coolant?

I would attempt to turn over the engine by hand to ensure nothing is overheated to the point of being jammed up. Then once confirmed to be freed up, bump start it...don't start it. Just to confirm the motor turns over. From there, I would replace the water pump and anything suspect while in there (hoses, thermostat, radiator cap, etc). Once topped off with coolant, actually attempt to start the car and see what happens,

kvshadow7

Well, the coolant on the reservoir tank was at full. I was in the middle of nowhere at night after my first stop where I noticed the open radiator cap. Some coolant leaked from the open radiator cap, but wouldn't the radiator get filled from the coolant reservoir? I'm still waiting on a full breakdown of what happened from the dealer.

kvshadow7

Thanks for your reply. The coolant reservoir was at the full mark, but probably the radiator wasn't full. I'm worried that as I tightened an open radiator cap with a coolant leak, I trapped all the air in the system and caused problems for coolant circulation. I know that HG replacement is very labor-intensive and probably will be hard to tell cracks or warpage in the engine head/ block. I will point out to the dealer to check the radiator for leaks. The car is at the dealer for now for a full diagnosis, and I'm not very good with engine mechanics to turn it over by hand. Would you also recommend installing a low mileage used engine? Should I install a new thermostat, ECT sensor, the serpentine belt, and a water pump as well?

LeX2K

No, you need to diagnose the problem before you start tossing parts at the car. You didn't cause any issues by removing the radiator cap.

bazzle01

Loose cap prob let the coolant out. You didnt notice as no coolant on sensor.
Doing the cap up without checking radiator level is prob the issue here.
No it wont automatically refill as you have already noted due to air entrapment.
Sadly it looks like you didnt check under the hood earlier and spot the issue.
As recommended above refill and ensure system is bled properly. Then retest to see if any issues still there.
Following this a trip to a repair shop would be a good idea.

jgscott

iTrader: (1)

Get the entire system pressure tested and bled.

2013FSport

iTrader: (2)

The reservoir is not the block. The block lost coolant from the cap being loose ans was not properly refilled before driving leading to all of the issues stated..

Note: the ONLY time the block pulls coolant from the reservoir is during engine cool down and it only does that if there are no leaks and a cap that seals at all three locations.

The simple explanation is a partially full water bottle in the sun, moved to the fridge. Notice how it collapsed? Hot water expands, when cooled, it contracts. That's when the block refills.

Buy a new cap, have the system pressure tested, have it filled and bled properly. Per Gville, also make sure the engine is not seized up.

GL