ls mark stephens hi guys time for more questions once again heres what i have for reference sake coupe ls k miles on the car engine rebuilt at k we bought the car a few months ago we are new vetters and quite addicted already we live in hot arizona and today was really the first day i had drove it for a for a pro longed period in traffic about miles the temp guage was arount sometimes a little over sometimes a little under is that a normal opperating range i stopped the car twice once for gas once to show off a little it's hard to be humble both times the car spit out what i would guess to be quart of anti freeze through the over flow when i got home i let it cool down enough to open the radiator cap on the factory metal over flow it was full i should also say it was very clean looking no rust just flouresent looking how do i know how much fluid is in the radiator theres a small hose feeding the top right hand side of the radiator there are also two larger hoses or i think connected to the bottom i looks like the heater hoses the one heater hose coming from the water pump has a shut off valve this is from the previos owner is this a problem actually i would'nt mind by passing the whole heater section is this possible is it a bad thing to do remember we live in az and really never need heat in fact my vents and fan blower dont work thats a future project if i by pass the heater core can somebody be kind enough to explain and or illustrate how to do it and my last question the previous said he used aviation fuel because of the high compression today i got some gas octane from chevron and after a few miles the engine staerted to knock when i accelorated so i drove home very modestly are there any recommended additives thanks in advance mark marks alphitech com to see our vette goto http www neta com iguana
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Re: 1970 LS5
re ls w that operating temp is about normal for a mine does the same burping of anti freeze if i shut it down while it is hot mostly this occurs when i have overfilled the system while cold if it only does it once not to worry the problem would be when it occurs at every engine cut off another trick if it has been running at a constant highway speed is to let the engine idle for a few minutes before turning off this allows the coolant to return to the radiator -
Re: 1970 LS5
re ls ed jennings many years ago i owned a ls which is essentially the same engine except for the lower compression ratio it had a thermostat and ran at with the air on in florida in the summer some big blocks were indeed subject to overheating some things to check are all the fan shroud pieces in place including the seals this is important and one of the evolutionary changes in the big blocks the problem was greatly reduced on the later cars also since you are having a detonation problem check your timing to make sure it isn't excessivly advanced your engine can probably be tuned to run successfully on octane but the original valves won't like the unleaded gas there are a jillion things that can cause overheating but the big thing in the vette is airflow good luck edComment
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Re: 1970 LS5
re ls j wright another possibility would be a vacuum leak some where in the extensive system of windshield wiper door headlight door systems that your car has i know from experience that one of these leaks can cause all kinds of problems including running hot and detonation if this seems to be something you would like to pursue feel free to contact me jimComment
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Re: 1970 LS5
re ls jack humphrey more detail on ls is helpful like presence of at or a c options which called for cooling system variations hint first determine if car is actually running hot many many corvette owners swear these cars just ran hot all the time not true modern hvac folks typically have temp guns that'll accurately read temperatures via ir you point pull the trigger and bingo you get a pretty accurate temp reading consider finding out what temp the rad hose is acutally seeing and comparing this to what you guage says next if you overfill the system with coolant owner's manual says how much expansion room to leave the system will naturally purge itself puke as we say on engine shut down so don't take this as proof positive that the engine's really running hot second next where did you get your temp sender most just go to chevy and order one or get one through a parts catalog look closely at the paragon catalog and note their disclaimer that these are new ac parts and can do drift off actual temp by up to degrees if your go to a scarp yard and pull real mccoy ac originals from engine blocks you'll see a small band off non threaded overhang just below the hex fitting put on reading glasses and you'll see the ac p n and a curious set of marks these seem to be a manual temp range sorting id one two or three id code wacks i've seen many a chronic overheating corvette that did not physically overheat in use mysteriously cured after much guessing and parts replacement by someone putting a one coded original ac temp sender into the block last next make sure you have correct fan working fan clutch all the air dam foam rubber components the aim called for around your radiator then look carefully at the radiator to make sure its fins are free of caked pushed in debris and the fins are actually straight to allow air to flow easily there are other areas to check but this is a good list to start with i've seen guys spend 's even 's without sucess only to find they were chasing their tails in the first place thinking taking for granted the car was in a condition factory designers intended it to be and tossing at finding the one item that was faultyComment
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