older 85 chrysler overheating

[river rat 26]

older 85 chrysler overheating

this is a buddy's mtr, he has checked and replaced all the usual stuff but mtr still overheats above 4800rpm. any one know of a good flushing solution (this is a 100% salt water mtr) thinking he has some sort of build up causing this.

 

[JB]

Re: older 85 chrysler overheating

Re: older 85 chrysler overheating

Moving to Chrysler Troubles

 

[jim dozier]

Re: older 85 chrysler overheating

Re: older 85 chrysler overheating

You say he has checked the usual stuff which I will assume includes:<br />-water pump impeller and housing<br />-thermostat<br />-clogged intake<br />-removal of previous lost impeller blades<br /><br />If it still overheats check<br />-water tube grommets<br />-head gaskets<br />-exhaust cover gaskets<br />-power head base gasket<br />-any pressure relief valves in the head<br />-ignition timing<br />-carburetion

 

[river rat 26]

Re: older 85 chrysler overheating

Re: older 85 chrysler overheating

hey jimd, thanks for the response. my old buddy mike replaced the impeller twice,replaced the t-stat & tried running without it, says the intake is clear, replaced head gasket, looked everywhere he could see for blockage, says he reinstalled the lower unit very carefully so i assume the grommets are in place..........mtr is running sweet, do you think carberation or timing could be a factor?......also powerhead & exhaust gaskets have not been replaced, are these real possibilities? mike has owed this mtr for years and done all repairs himself

 

[river rat 26]

Re: older 85 chrysler overheating

Re: older 85 chrysler overheating

jimd, are we taking about leaks we could see on these gaskets or should they be replaced just to eliminate them as possibles

 

[scotiany]

Re: older 85 chrysler overheating

Re: older 85 chrysler overheating

You should check the water pressure relief valve in the head at the water jacket. The Seloc manual says this valve being stuck shut in older motors is common. Especially if used in salt water. It's not easy to fix. You really need a manual for this proceedure.

 

[river rat 26]

Re: older 85 chrysler overheating

Re: older 85 chrysler overheating

thanks scotiany, he never mentioned cking a relief valve, i'll give him a heads up on this

 

[river rat 26]

Re: older 85 chrysler overheating

Re: older 85 chrysler overheating

ok mike has also eliminated the relief valve as a culprit, he is not real exited about replacing the powerhead or exhaust gaskets with out first identifing them as a problem, is there a way to be sure? mtr. ran at a higher rpm before getting the horn with the t-stat removed which seems to indicate that he is just not circulating enough water. is there any safe chemical mix out there for flushing that won't eat anything important? thanks again, river

 

[jim dozier]

Re: older 85 chrysler overheating

Re: older 85 chrysler overheating

There is a product out there called Salt-Away. I have no experience with it but I am familiar with the chemistry and I suspect if it has any utility it is in prevention not cure. Deposits in the cooling system of aluminum engines run in salt water are oxides and carbonates of aluminum and a little caked on salt. The salt deposits aren't the problem because they are very soluble in hot water and quickly wash away but they chemically accelerate the formation (corrosion) of the aluminum oxides and carbonates which are very hard and relatively insoluble in water. These deposits can block the cooling channels in older engines and engines not flushed after use. Having mechanically removed these deposits in my own engine I can attest to their durability and I have even tested removing them with muriatic (hydrochloric acid) acid on the bench with the parts removed. The problem is that aluminum is about as soluble in acid as the corrosion is, and the aluminum tends to preferentially dissolve in places with more surface area(joints, cracks, holes) where you wish it would not, and the deposits don't dissolve because they have less surface area. The bottom line is, anything really strong enough to get in there and eat the deposits is probably gonna etch your block where you don't wan't it to. If you have clogs remove the part and remove them with a tool.

 

[river rat 26]

Re: older 85 chrysler overheating

Re: older 85 chrysler overheating

gotch ya jimd, no easy way out. ok we will go to work, i'll let you know the outcome........

 

[river rat 26]

Re: older 85 chrysler overheating

Re: older 85 chrysler overheating

mike replaced his stock temp sending unit with a sender and a guage, said the stock unit looked fine in the block but when he removed it it kind of crumbled into pieces. we hit the lake today armed with a raytec. we ran it wfo for 30 min with the cowling on then removed it and took temp readings while running down the lake. with the lake temp at 74 highest reading i got was 180 right at the head (all cylinders) about 140 on the t-stat housing& exiting water temp never got above 140. seems like the stock sender may have been the problem. what do you think?

 

[scotiany]

Re: older 85 chrysler overheating

Re: older 85 chrysler overheating

Maybe you found the problem. Sure sounds like it. Water temp at thermostat around 143-145. Did the warning light/horn come on. If not. run that sucker. Sounds like you got a winner.

 

[river rat 26]

Re: older 85 chrysler overheating

Re: older 85 chrysler overheating

he is headed to the coast this weekend, running it in that warm water down there ought to let him know one way or the outher for sure. when he installed the guage he did away with the stock sending unit so with no horn he's gonna have to keep an eye on the guage........the anti-chrysler lives (i don't see why anyone messes with these with all the fine old rudes around) don't tell mike i said that, he's a big boy and this is his pride and joy

 

[jim dozier]

Re: older 85 chrysler overheating

Re: older 85 chrysler overheating

I'd say that motor is as good as its going to get. Temps are right where they should be.