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  1. #16
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    Quote Originally Posted by 2005rtmag View Post
    i don't see why using a lower temp thermostat won't keep the aluminum head cooler which is the objective. The seat temp being high is ok. It helps keep the seat tight in the head, it's the aluminum head temp that needs to be kept lower to keep it from expanding and releasing the seat. Aluminum transfers heat very quickly. But, I think you need a larger radiator to go along with the lower temp thermostat to make sure the peak temp on a hot day doesn't go too high.
    That's what I was trying to express, thank you. I don't know for sure but it seems a feasible enough hypothesis to at least warrant consideration.

    My build sheet from the dealer lists a heavy duty radiator, perhaps the original owner option was a radiator for the 6.1?



  2. #17
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    The heavy duty radiator is the standard RT radiator. The 5.7 cars with a tow package and police cars came with a severe duty radiator which will drop in. the SRT radiator is a severe duty II which has larger connections which will require SRT hoses.
    Thanks Jon Richard thanked for this post

  3. #18
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    Much appreciate the info there!

    If I figure out the actual measurements of the factory 5.7 valve seat and bore I'll post a follow up. If anyone already has this info please post.

  4. #19
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    Quote Originally Posted by Jon Richard View Post
    The strawman remark was not meant as a sleight, I was defending that I never took the position that a T-stat would alter localized chamber temps. Sorry if you feel I was being condescending toward you Hemissarry. You did come across as believing this is a non issue very strongly, that's what I meant about dismissive. I'm going to chalk this up as communication breakdown that happens often with short form written exchanges.

    I may decide to do head work and if so I will post, but again I have nothing to prove as I'm not taking a position. You are declaring very adamantly that this is a non concern, all I'm asking is that you present these facts you're referring to to enforce this claim.

    I am truly perplexed as to how this became a contest, was definitely not my intent to argue or offend. All I can tell you Hemissarry is that I am hearing and reading about potential valve seat issues in the gen3 5.7 and all one can do is go off the information available to them. If you have better information about the pre eagle 5.7's myself and I'm sure others would like entertaining it.
    Not slighted :^)

    A simple search of this Forum would reveal this topic has been discussed ad-nauseum for years. The root cause is known. The number of failures versus the number of Hemi's produced though 08' is known. Daimler-Chrysler knows of the issue; hence no CSN or TSB. Few realize all other Marques have similar failures (again - search is your friend).

    I will say, for the last time here (until this issue again gets airtime) that the odds of experiencing a failure rival winning the Lotto. So worrying about a serves no one...least of all the person who elects to worry cause they read of it periodically - when someone elects to post about it...again...and again.

    If the worry is of the magnitude that it motivates you to do pull the heads and have them reworked - go for it. If the work has been performed correctly (and we've already read where it hasn't) and the rest of the R&R has been performed correctly (where we've that hasn't always been the case) the engine is likely home-free. At least on this issue alone...

    Worrying about it - knowing full-well you will never break into the engine to act on that worry - serves no one.


    Quote Originally Posted by 2005rtmag View Post
    i don't see why using a lower temp thermostat won't keep the aluminum head cooler which is the objective. The seat temp being high is ok. It helps keep the seat tight in the head, it's the aluminum head temp that needs to be kept lower to keep it from expanding and releasing the seat. Aluminum transfers heat very quickly. But, I think you need a larger radiator to go along with the lower temp thermostat to make sure the peak temp on a hot day doesn't go too high.
    Understanding that Aluminum alloy has a significantly different coefficient of expansion per degree than metal alloy (there are distinct advantages to powdered versus cast) is important as it relates to securing one into the other. So the initial clearance and installation process is as important (powdered are easier to press in for starters). Understand that right(!) at the cylinder head / coolant interface - the greater the difference in temperature the more thermal energy is transferred to the coolant by convection.

    However; in order to understand that temperature delta, you can't simply look at it as the difference between a 200F and a 190F T-stat. In order to properly compare this delta (e.g. 200F --> 190F - 10F) you must put it on the same scale. This requires measuring using thermodynamic energy using the Rankin scale (for Fahrenheit −459.67° versus Celsius @ −273.15C - both equal absolute zero).

    So - for a change from 203F (OM) T-stat to say a 190F unit means -460F + 203F = 663F. The 190 T-stat works out to -460F + 190F = 650F. This means a delta (change) of 13 degrees. This works out to:

    650/663 :: X/100 = a change of only 1.96%.

    Whether that rounded 2% change in thermal efficiency equates to enough of a change in the coolant temperature when it comes across the backside of any of the intake valve seats on the inside of the cylinder heads....I think you get the idea yes? SO what is 2% gonna do? Given coolant circulates throughout the engine, at what point under a full-throttle / maximum load application where the energy (in Joules) being imparted to the aluminum / coolant interface is 2% going to affect? Even with a 160F T-stat its still only `6.5%.

    Simply - a 10F drop at the T-stat even if this was the actual resulting coolant delta - will never be observed directly behind any seat / cylinder interface.

    Quote Originally Posted by 2005rtmag View Post
    The heavy duty radiator is the standard RT radiator. The 5.7 cars with a tow package and police cars came with a severe duty radiator which will drop in. the SRT radiator is a severe duty II which has larger connections which will require SRT hoses.
    HD: SXT and RT standard radiator
    Severe Duty: 6.1 SRT and some commercial contract LX platforms (not all)
    Severe Duty II (otherwise MAX Duty): LX platforms destined only for hot climate offshore sales (these radiators had specialized hose fittings that precluded their use here - unless you knew what to order).
    Last edited by Hemissary; 09-13-2019 at 10:53 PM.
    2005 Magnum RT---Viper Venom Red----440ci Aluminum block----Short Runner Valve Intake--410mm BAER 6S Monoblock Extreme--Eibach Multi-Pro 2

    Custom--Grille Work--Hood--Headlights--Side View Mirrors--Rear Spoiler--Rear Diffuser--SRV Control System--Turbine Wheels


  5. #20
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    Quote Originally Posted by Hemissary View Post
    Not slighted :^)

    The number of failures versus the number of Hemi's produced though 08' is known. Daimler-Chrysler knows of the issue; hence no CSN or TSB. Few realize all other Marques have similar failures (again - search is your friend).

    I will say, for the last time here (until this issue again gets airtime) that the odds of experiencing a failure rival winning the Lotto.






    HD: SXT and RT standard radiator
    Severe Duty: 6.1 SRT and some commercial contract LX platforms (not all)
    Severe Duty II (otherwise MAX Duty): LX platforms destined only for hot climate offshore sales (these radiators had specialized hose fittings that precluded their use here - unless you knew what to order).
    The number of valve seat drop failures are not known. There is no way anyone could know that number.

    I didn't realize that there were so many lottery winners on this site!

    My post on the radiators is correct. The severe duty II radiator is in the SRT. Look up the part numbers. There was a very large export only radiator but it was in addition to the heavy duty, severe duty, and severe duty II.

  6. #21
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    Quote Originally Posted by 2005rtmag View Post
    The number of valve seat drop failures are not known. There is no way anyone could know that number.

    I didn't realize that there were so many lottery winners on this site!

    My post on the radiators is correct. The severe duty II radiator is in the SRT. Look up the part numbers. There was a very large export only radiator but it was in addition to the heavy duty, severe duty, and severe duty II.
    Agreed; there is no feasible means of figuring out how many valve seat failures Dodge 5.7 or even 6.1 engines...or more interestingly 5.7 liter-equipped Vipers (did anyone catch that :^) have experienced valve seat failures. You kinda make my case

    Given you have been involved in previous discussions on here about this, I'm curious what your motives are. Does DC (then) or FCA (now) owe you something? Let me make this as clear I possibly can; my responses back-to-front are about those readers on here who see the thread title and their concerns rise. What's the point? Its pretty clear that the failure frequency is not going to change in relation to units per mile. not everyone understands the technical reasons or even f'n cares. All those who are in that window know is that their ride is on the radar for potential failure. The facts favor overwhelmingly not to R&R the valve seats. What disappoints me is that more readers on here who are in-the-know elect not to chirp up. Why people keep knowledge to themselves?

    A great counter to this would be to ask everyone to post that their 04' - 08" 5.7 Hemi engines are still going strong. I'm sure they got other things to do. I'm not gonna :^)



    Oh yes - there's a great thread from the early days on here about a thousand pages long started by Matt. Its all about the LX cooling system; it has real PNs...
    Last edited by Hemissary; 09-14-2019 at 02:33 AM.

  7. #22
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    I'm a 75 yr old retired engineer and mostly brand neutral when it comes to cars and trucks. When I see someone post that the likelihood of a valve seat drop in the 5.7 is about the same as winning the lottery (1 chance in 300 million), I do say something. I bought my 05 Magnum new and still love it and it has not dropped a seat yet. I won't be rebuilding my heads because of the chance it might happen. I'll probably just sell it to a salvage yard if it does happen. Perhaps because I am an engineer, I like to know all the potential weaknesses or issues in something I own. I posted that link because I thought it was interesting and might be interesting to other owners who are car people or they would not be on this site to begin with.

    As far as radiators, I just looked at the moparpart.com web site and it does list 4 radiators.

    Radiator & Components for 2006 Dodge Magnum | MoparPart
    Last edited by 2005rtmag; 09-14-2019 at 09:39 AM.

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