Head Gasket or Radiator?
 

My 1989 D350 Cummins 5.9L 12V engine 181,000 miles.

I've got to get this truck back on the road ASAP. I'm in the middle of a renovation job, and my girlfriend needs me and the truck to move in a few days. This is my dilemma..
Two months ago, I noticed the antifreeze was brown and rusty, so had a local mechanic change the fluid and test the radiator for leaks. He said the radiator was not leaking.

A month ago, I noticed the truck was getting hot during a 6 hour drive on the highway. The temperature kept creeping higher until it was nearly at maximum on the gauge. The coolant was nearly two gallons low.

After monitoring the coolant level, the engine is losing about 1/4 gallon antifreeze every 120 miles.
There was one instance, where the antifreeze blew out of the radiator cap while driving which was noticed from newly, dried, antifreeze on the underside of the hood.

This time the truck was taken to a diesel mechanic who did a pressure test. The mechanic told me that the truck dropped 7psi in 10 minutes, that the factory spec was 1psi in 1 hour. The mechanic recommended a new head gasket, cylinder rings and push rod bearings for $3000-$4000 and 1 week to complete the repair.

Not having that money, and following the head gasket instructions on Diesel Forum", I purchased a head gasket and head bolts.

While starting the repair. It was discovered during draining of the Antifreeze and Oil, that there is no contamination from one to the other. Antifreeze is rusty but not oily, and Oil is pure.

It was also Discovered that the radiator has green streaks in 7-8 places, so there is seepage. Also big chunks of debris came out while draining. Contrary to what the first mechanic said and the second mechanic did not mention\'85the radiator needs to be replaced!

My wishful thinking is that the lost antifreeze is only an issue with the radiator and not the head gasket or cylinder rings.

Question 1. Do I proceed with replacing the head gasket at this point or simply put a new radiator in and see how the truck runs? \

Question 2. While Radiator is out, what other parts should be replaced? Such as water pump, radiator hoses, serpentine belt? Anything else?

If the diesel mechanic was competent and honest, I would think he would have mentioned the radiator issue rather than suggesting the $3-4k overhaul. The truck seems to start fine without issue so I'm not sure the head gasket is bad. There is some white smoke upon acceleration. At this time there is not any external leak, or mixing of the antifreeze and oil, but I suppose if just a little antifreeze was entering one of the cylinders that it would burn off and not get into the oil\'85 Is this correct?

Question 3. One area of concern. The antifreeze upper hose engine block mount is so rusty that the hose had to be cut off. The metal is expanded, rusty and flaking. Could this be caused by the truck sitting or using water instead of antifreeze? Should the rusty part be replaced or repaired? What other internal parts could be rusty and need to be in bad condition?

Welcome Dave to the board.

Here is my thoughts. It is very possible that you have a bad head gasket, using 1/4 gallon, or about a liter, every 120 miles makes me think it could be more then a bad radiator. But if you do have that many leaks, and they are fine enough, you could be evaporating most of the fluid before it hits the ground.

The rusty water is most likely due to you not using any antifreeze...at least that is how I read your post. Definitely run antifreeze since it has anti-corrosion properties. I always run a simple 50/50 mix. And just recently switched to distilled water, instead of city/well water.

I think I would take a gamble on the radiator and cooling system, before I would do the head gasket. If you do decided to go with a new radiator, i would also install a new water pump, upper and lower rad hoses, and a new thermostat, or at the very least remove the current T-stat and clean and test in a pot of boiling water. Then re-seal the T-stat housing.

As for the hose end on the top of the motor....yes most likely rusty due to age, and just water in the cooling system. I would just clean the scale off really well, chip and sand it clean, then paint it with rustoleum/tremclad. Then install new hoses and clamps.....maybe a double clamp on the rusty end though?

Also installing a new fan clutch couldn't hurt either. And are you still running the factory shroud?

take the radiator cap off and start the engine. if it blows out of the top of the radiator, you have a blown head gasket.

what is the exhaust like? white? smell sweet like antifreeze?

with the cooling system sealed up, watch for leaks once the system has pressurized. meaning run it until it's hot and then look around

I believe he has already started his repairs to the engine so any further testing may be
difficult,

The first thing I would have done was a combustion leak test to see if there were any combustion byproducts in the coolant to rule out the head gasket,

Have you checked the radiator cap?
Does your exhaust smell like coolant?
Is there any oil or sludge in the recovery bottle?

I have a hard time trusting any of the mechanics especially when it comes to a Cummins, lots claim to be experts but have never touched one

Jim

I think your mechanic is dishonest.
1. Cylinders don't have rings, unless you count an o-ring in a wet sleeve engine, which this is not. Pistons have rings, and they are replaced to deal with oil consumption and loss of compression. They have nothing to do with coolant loss.
2. Push rods don't have bearings. Connecting rods do, and they are replaced to deal with engine knocks or loss of oil pressure, and have nothing to do with coolant loss.
3. As was said, an exhaust gas test will disclose a leaky head gasket when the leak is so small it's hard to notice. It's a simple cheap chemical examination of the air over the coolant in the radiator. It's done by all reasonable shops, including 1 stall garages.

If you deal with road salt, the liklihood that your radiator is in reasonable condition is nill. If you've been running water, and the system has not been maintained, which is obvious, the radiator is toast.

Scaly rust on cast iron hose bibs is pretty normal. Chip and sand it off, put a little paint on it, or just put it back together sans rust. Won't hurt, and really doesn't tend to use much metal for the mess that it is.

Sorry to hear that you're so far into it before getting sound advice.

^This^

D350 Head Gasket or Radiator..Answers to Answers
 

d350 head gasket or radiator. THANKS FOR THE ADVICE!!

The following are answers to your questions.

J.fonder
The truck is not running, the radiator is removed, I started to loosen the injector bolts & turbo as well as other passenger side of the truck components for changing the head gasket. It is not so far along that it cannot be put back together and the tests you recommended can be performed to conclusively identify if it is the radiator or a head gasket leak.

At this point the radiator will be replaced. The current radiator cap is rated at 16psi. I'm not sure if that is to the recommended specification. I’ve ordered the Dodge shop repair manual, but it has not arrived yet.

—
Thrashingcows
It has been running anitfreeze since the first mechanic checked the radiator a month or two ago. The previous owner probably was not using antifreeze. It was a california truck so only surface rust on frame & body. The previous owner did not have to worry about freezing temperatures.

Yes, it does still have the factory shroud, and it was the original radiator too.


Your advice to replace the fan clutch is appreciated.
——
Jim Lane
No sludge in the recovery bottle
exhaust smell is not of coolant, but that could change when accelerating and that is when the white smoke is more noticeable.

Will plan to do a combination leak test
Regarding the diesel mechanic, it is a big shop, that works exclusively on trucks and overhauls Cummins so they are knowledgeable with Cummins.

Thank you for the advice on the combination leak test!! I had not heard of that one.

——
j_martin
Will sand the hose bibs and paint with rustoleum.

Regarding my comments about cylinder rings. That was my error. It was piston rings that he was recommending and connecting rod bearings as you pointed out. He said it and didn’t write it down so I probably mixed the terminology up a bit.

Great recommendation on having a chemical examination done!


****
I want to thank each one of you for the quick replies and expertise in offering your advise. It is appreciated. The undertaking of changing the head gasket is a sizable challenge that I'm not sure how long it would take to successfully see through to completion. Not too mention my having pressure to get the truck on the road.

In the meantime, I'm keeping my fingers crossed.
I'll let you know how the tests turn out after the replacement radiator is installed.

****
One additional Question.

While the Radiator is out, should a KSB kit be installed? I read that it only effected 1990 & 91 trucks, but another source said 1989 as well.

The truck will remain stock and not high performance.

The radiator pressure is limited by the radiator, hoses, heater core, etc. I have a high perf Mishimoto radiator and a 19 lb cap on mine.

White smoke under acceleration is might well be due to a clogged fuel filter or bad fuel lift pump.

You probably need a new radiator, as has been said.

I also bet your oil cooler is probably leaking -- the rectangular plate with the oil filter mount that bolts to the side of the block. If it has crud all over it, the crud is probably coolant, not oil. And if it was straight water in the truck, it would just evaporate away if the cooler was leaking.

Also, if the truck is an automatic (sorry if you specified & I missed it), have you checked for water/coolant in the transmission oil?

All good advice and from some of the most knowledgeable on the board.

With the radiator out you might as well kill the dowel pin, it'll never be easier. What I don't know is if the year you have needs it like you say. I thought all the 1st gens did and some of the 2nds?

The KSP kit?
Or do you mean the KDP - Killer Dowel Pin.
The KDP effects all 12Vs, as the dowel is used to help install the timing case at the factory.
I see more KDP problems on the 2nd gen 12Vs.
In my own head I attribute that to the super big and heavy P-pump injection pump which adds more weight and stress to the aluminum timing case….Maybe?

Now would be the time to do it with the radiator out.

Oh yea he did write KSB, I just read it as KDP I guess. Not sure what a KSB kit is???

KRB, even though KSB was written, "KDP" was the part I was asking for input on.
Since last posting. An original, direct replacement, radiator made of brass/copper was ordered. As was a new water pump, clutch fan, radiator upper and lower hoses. It should arrive by tomorrow. I was hoping to get it back up and running over the weekend and be able to update you on whether there is additional work needed.

It is heartening to have all the knowledgeable advice, as well as the added incentive of being able to share the results with you all!

PS: The dodge service manual arrived in the mail.
PSS: Alec. I'll have a look at the oil cooler for signs of a leak.

Glad yo got all the parts on the way, and I hope it solves your issues! :thumbsup:

And please share your results...pics are always welcome...;)

Any luck Dave?