I just want to start off by mentioning that I have read through @Jorgito super thorough and helpful head gasket post from a while back. I also have the FSM and OTRAMM videos for reference.
A little back story (kind of lengthy but please stay with me because I need help), I purchased this 125k mile 40th anniversary back at the end of 2025. It was a one owner and they provided a decent number of service records. The only thing they excluded was the use of head gasket sealer in the cooling system... (in hindsight the vehicle was driven to the meet up location and running when I went to purchased so I failed to check the cooling system before purchase. Noob mistake but we are here now trying to fix the problems) The AC was cold and the truck was running at normal temps even under load so I wasnt overly concerned at the time.
My goal was to do a basic tune up. I have an LX 450 that I have done tune ups on in the past so my plan simply went from tune up to tune up and flush with OEM parts. I thought I could simply add flush and overhaul the cooling system and that I would be good to go for a short time until I was ready to tackle the head gasket correctly. I bought a new OEM rad, hoses, water pump, Toyota red coolant, and thermostat. While I was at it I got in contact with @landtank and picked up a new blue fan clutch (currently located in coastal South Texas). I thought I was set. Problem solved, right? No, that would have been too easy. So after doing all this, I tested my cooling system and found exhaust gases contaminating the coolant. Although my oil was very clean i was worried that if I left the HG as it was I would end up with coolant in my oil and a ruined shortblock. That is how I got to this point. Pulling my head was the biggest job I have done by far. Up to this point my biggest job was probably the front main seal and oil pump gasket. I am definitely not a mechanic by trade but I would like to think that I am also not entirely clueless. Following the FSM, Jorgitos thread, and OTRAMM videos I was able to get my head off without much issue. I took my head to a machine shop and when I went to pick it up they mentioned that the head had definitely been off before and that it was definitely hit with a wire wheel rather than a proper decking process. The machine shop mentioned that they had to take 0.08 off to get the head flat but since it had been off before there is no telling how much had been removed overall. Along with this my vales and seats were slightly pitted. I had read both here on ih8mud and in the FSM that Toyota does not offer an acceptable head surfacing value. If its out of spec, it needs to be replaced... So I had a choice. Do I reuse the head with an unknown amount of material removed and hope I can lap the vales and seats to an acceptable value without screwing it up or do I buy a new head. I went back and forth but ultimately decided to go for the new head option. I was already $250 in the hole for the hot tank and decking of the old head and I was quoted anywhere from $650 to $900 for a valve job. Researching and finding all the necessary OEM parts was adding up to around $2000 after discounts and what not so the delta in price made the new head worth it in my opinion. I went ahead and purchased a brand new head and all necessary components to go with it. So now here we are. Head is off and I am prepping the short block mating surface for the new gasket. I know a lot of people say not to bother with cleaning the pistons but I went ahead and cleaned them. My actual question for the group pertains to my cylinder walls on cylinders 1&6. I started with cleaning pistons 1&6 since they were already at TDC. The cylinder walls on 2,3,4, and 5 looked very reasonable to me. However when I rotated my crank today in order to bring cylinders 2&5 to TDC I noticed that cylinders 1 and 6 seemed a little less "ideal". I have attached photos below but is this concerning or not a big deal? These photos are from cylinder 1. Although not identical, cylinder walls on 6 look similar to this with this being the more noticeable/concerning in terms of the brownish discoloration. I cannot feel any defect on the surface but I am still not sure how acceptable something like this is. I am unsure if water or anything else sat in the cylinders at any point. I also don't know if this happened because I have had these two cylinders sitting at TDC for about a month now with the head off living near the ocean or if this is completely unrelated. Any input in appreciated. I don't know if it makes a difference but I tried manually checking each piston for play against the cylinder walls and they all seem snug. I added a mix of atf/acetone to all the cylinders including 1 and 6 and they all still had a decent amount of the mixture in the cylinders 2 days later. I had previously posted this on Jorgitos older thread but @Kernal made a great point that I will likely get more traffic if I start a new thread rather than posting on page 15 of decade old thread haha. Thanks everyone.
A little back story (kind of lengthy but please stay with me because I need help), I purchased this 125k mile 40th anniversary back at the end of 2025. It was a one owner and they provided a decent number of service records. The only thing they excluded was the use of head gasket sealer in the cooling system... (in hindsight the vehicle was driven to the meet up location and running when I went to purchased so I failed to check the cooling system before purchase. Noob mistake but we are here now trying to fix the problems) The AC was cold and the truck was running at normal temps even under load so I wasnt overly concerned at the time.
My goal was to do a basic tune up. I have an LX 450 that I have done tune ups on in the past so my plan simply went from tune up to tune up and flush with OEM parts. I thought I could simply add flush and overhaul the cooling system and that I would be good to go for a short time until I was ready to tackle the head gasket correctly. I bought a new OEM rad, hoses, water pump, Toyota red coolant, and thermostat. While I was at it I got in contact with @landtank and picked up a new blue fan clutch (currently located in coastal South Texas). I thought I was set. Problem solved, right? No, that would have been too easy. So after doing all this, I tested my cooling system and found exhaust gases contaminating the coolant. Although my oil was very clean i was worried that if I left the HG as it was I would end up with coolant in my oil and a ruined shortblock. That is how I got to this point. Pulling my head was the biggest job I have done by far. Up to this point my biggest job was probably the front main seal and oil pump gasket. I am definitely not a mechanic by trade but I would like to think that I am also not entirely clueless. Following the FSM, Jorgitos thread, and OTRAMM videos I was able to get my head off without much issue. I took my head to a machine shop and when I went to pick it up they mentioned that the head had definitely been off before and that it was definitely hit with a wire wheel rather than a proper decking process. The machine shop mentioned that they had to take 0.08 off to get the head flat but since it had been off before there is no telling how much had been removed overall. Along with this my vales and seats were slightly pitted. I had read both here on ih8mud and in the FSM that Toyota does not offer an acceptable head surfacing value. If its out of spec, it needs to be replaced... So I had a choice. Do I reuse the head with an unknown amount of material removed and hope I can lap the vales and seats to an acceptable value without screwing it up or do I buy a new head. I went back and forth but ultimately decided to go for the new head option. I was already $250 in the hole for the hot tank and decking of the old head and I was quoted anywhere from $650 to $900 for a valve job. Researching and finding all the necessary OEM parts was adding up to around $2000 after discounts and what not so the delta in price made the new head worth it in my opinion. I went ahead and purchased a brand new head and all necessary components to go with it. So now here we are. Head is off and I am prepping the short block mating surface for the new gasket. I know a lot of people say not to bother with cleaning the pistons but I went ahead and cleaned them. My actual question for the group pertains to my cylinder walls on cylinders 1&6. I started with cleaning pistons 1&6 since they were already at TDC. The cylinder walls on 2,3,4, and 5 looked very reasonable to me. However when I rotated my crank today in order to bring cylinders 2&5 to TDC I noticed that cylinders 1 and 6 seemed a little less "ideal". I have attached photos below but is this concerning or not a big deal? These photos are from cylinder 1. Although not identical, cylinder walls on 6 look similar to this with this being the more noticeable/concerning in terms of the brownish discoloration. I cannot feel any defect on the surface but I am still not sure how acceptable something like this is. I am unsure if water or anything else sat in the cylinders at any point. I also don't know if this happened because I have had these two cylinders sitting at TDC for about a month now with the head off living near the ocean or if this is completely unrelated. Any input in appreciated. I don't know if it makes a difference but I tried manually checking each piston for play against the cylinder walls and they all seem snug. I added a mix of atf/acetone to all the cylinders including 1 and 6 and they all still had a decent amount of the mixture in the cylinders 2 days later. I had previously posted this on Jorgitos older thread but @Kernal made a great point that I will likely get more traffic if I start a new thread rather than posting on page 15 of decade old thread haha. Thanks everyone.
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