New head

WWDiesel · **Posted:** Sun Apr 10, 2016 8:59 pm

I think that the addition of the 11 blade mechanical fan, either a Mopar or GM unit, with the addition of the proper Hayden heavy duty fan clutch is worth every penny spent to help cool these motors.... I personally would never advocate the removal of the mechanical fan!!!! Based on the posts, I certainly would not opt for the inline thermostat... :shock:

flash7210 · **Posted:** Sun Apr 10, 2016 9:27 pm

Driftless Tad wrote:

Well, add me to the inline t-stat crowd!

I just put one back in and I think it might be coming right back out.

Thats four, confirmed.

ATXKJ · **Posted:** Sun Apr 10, 2016 9:49 pm

Well I had a cracked head - totally stock - thermostat and cooling - never overheated.

and I've run the inline for the last 50,000 miles without any problem.

flash7210 · **Posted:** Mon Apr 11, 2016 7:54 am

ATXKJ wrote:

Well I had a cracked head - totally stock - thermostat and cooling - never overheated.

and I've run the inline for the last 50,000 miles without any problem.

Tally is now...

4 -cracked heads while using inline thermostat.

1 -cracked head with stock only thermostat.

funnyman06 · **Joined:** Sun Jul 06, 2014 7:46 pm **Posts:** 180

That should be 2 with the stock T-stat. However I dont believe the T-stat had anything to do with my failure.

ATXKJ · **Posted:** Mon Apr 11, 2016 2:11 pm

yeah I don't think the T-stat had anything to do with mine either

- not impressed with the entire Thermostat - cracked head theory

flash7210 · **Posted:** Mon Apr 11, 2016 2:21 pm

ATXKJ wrote:

yeah I don't think the T-stat had anything to do with mine either

- in fact I think the Thermostat - cracked head theory is a wild goose chase.

and the comments in this thread are classic confirmation bias.

I'm willing to accept that the cracked heads are due to poor manufacturing.
But then you have to wonder why folks in England and Austrailia are not reporting any cracked heads?
(or dropped valves)
And what can be done to prevent it from happening?

ATXKJ · **Posted:** Mon Apr 11, 2016 2:41 pm

in my case I'm pretty sure the root failure was a broken glow plug

it was under extended warranty - and so I never saw the head - Chrysler got it back

and considering the money they spent on it I suspect it got a reasonable failure analysis

so I think mine (and Darbys and few others) were to root of the '5v' glow plug

but you end up with the same question - why don't the UK/Oz folks have glow plug fails?

flash7210 · **Posted:** Mon Apr 11, 2016 3:03 pm

Funnyman:

Quote:

My head cracked as well, but i believe that it was due to coolant entering the combustion chamber through a failed EGR cooler.

ATXKJ:

Quote:

in my case I'm pretty sure the root failure was a broken glow plug

So, in both these instances, some other part failed, causing mechanical damage to the head.

In my case and the case of a few others, the initial diagnosis was a blown head gasket. The head itself showed no signs of damage. Only after testing were the cracks discovered.

So, what was the cause of the cracks?

Driftless Tad · **Joined:** Wed Jun 05, 2013 12:54 pm **Posts:** 22

Could be the difference in fuel quality between here and the rest of the world?

I have to say it is a bit disconcerting but if I can get another 190K out of this new head I'll be doing the banana dance. :BANANA:

I did drill the hole in this stat and I wonder if that has anything to do with failure or not. I did order a factory t-stat just minutes ago.

TURBO-DIESEL-FREAK · **Joined:** Sat Apr 17, 2010 3:29 pm **Posts:** 1167

Blocking both the main coolant circuit through the radiator and the bypass circuit by using an inline thermostat in conjunction with a failed O.E. thermostat assembly CONTRIBUTES to failed head gaskets and cracked cylinder heads.

For the record... I never claimed that the inline thermostat used in conjunction with a failed O.E. thermostat was the ONLY reason for failed head gaskets or cracked cylinder heads. There are many reasons for cylinder head/cylinder head gasket failures, especially on an engine with an aluminum head on an iron block. Simple overheating of the engine can do this, as can poor driving habits and extreme driving conditions.

I suspect that those who swear by the inline thermostat option tend to live in warmer climates and do not have as long a warm-up period as those of us running engines in far colder climates. Warmer climates are simply much easier on engines than colder climates.

Some members have posted that it is not a big deal that the R428 has an aluminum cylinder head; I could not disagree more. Aluminum expands about twice as much as iron, and therefore creates significant problems for any engineer trying to create an air-tight seal between the two metals as those metals heat up and cool down, as what happens in a head gasket. The cooling system must also be designed carefully to allow even warm-up of the engine and eliminate the creation of any hot spots that can exacerbate the differences in the thermal expansion properties of aluminum and iron.

While it is true that aluminum heads have been used on iron blocks for many years on passenger vehicles, the purpose for doing so by the manufacturers is simply to lose some weight off the engine. They most certainly are not doing it to make the engine more reliable; in fact, a strong case can be made that they are also using aluminum heads because they know an aluminum head on an iron bock is not as reliable as an iron head/iron block combination. They are counting on a significant percentage of aluminum head/iron block head gasket failures o the owner can come back and pay through the nose to get it fixed.

The above scenario is not the case with commercial or marine engines.

Reliability is a much bigger deal with the people who are in commercial transport or are on the water, and therefore these engines are almost exclusively iron head on iron block. It is much easier to have reliable cylinder head integrity when the metals on both sides of the head gasket have the exact same thermal expansion properties.

Also for the record, and as a reminder to those CRD members who are purchasing a replacement O.E. thermostat... The Factory Service Manual states that the O.E. thermostat assembly is designed to open up at 176 degrees Fahrenheit. This is way too cool for optimum operation - read that as fuel economy, reliability, and power delivery - of your R428 engine. Above 200 degrees is best.

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