Runs Hot - Out of Ideas

I feel your frustration.  This stuff gets personal.  I'm thinking you have some kind of baseline flow issue. You mentioned changing the pump and timing cover.  Any chance the pump is turning backwards?

What about obstruction /fitment /flow issues with the timing cover?

I know it's a new radiator but did you check it for flow?

Whatever you find please post the answer if you fix it

I bought a van one time that wouldn't heat the heater core up.  Took off the hoses feeding the core I could pee more than would come out with the engine running.  Traced it back to the threaded nipple  at the intake.  Took that out and what looked like an electrical knockout up inside it nearly blocking all flow.  It had 80k on it and it was probably like that from the factory?

Wife was much happier after that!!

I also found this

You have to be careful with some of the newer radiators on newer cars,Because they are NOT meant to flow that much for higher efficaincy reasons. They up the fin count, lessen the rows of tubes and "dimple" the tubes to actually slow the flow down so the coolant is in the core longer, having more heat pulled from it. Those radiators are hard to get a good flow check on.

The LA timing cover (magnum to) is only a platform to hold the pump, I have ordered the Pyrex 1-1/2" clear site tube to install in the upper radiator hose, that should allow a visual inspection of the flow. The FSR radiator (Tug model) I am using has been used by others on this site, it is the same base 3 row core as the one FSR builds as a direct replacement for the Dodge van just two inches shorter, has 50% more capacity than the original. Now it could be defective, looking inside the slits appear to be open, pulled the lower hose off once, lost half the coolant before I could get a pan in place, made a heck of a mess, flowed pretty good if you ask me.

The water pump is a new Mopar LA clockwise 6 blade, now unless ma Mopar made mine with reversed fins (?) I guess the glass tube will verify that also. Should have that chunk of glass here by Saturday.

Good Luck Busman, we're all rooting for you! Please let us know how this turns out cause one of us might have the same issue down the road. Please and Thank You!

I'm just thinking out loud here. You didn't happen to measure the bore when you had the heads off did you?

I'd be really tempted at this point to just pull that water pump and give it look and check flow through the block/heads

If I recall a radiator repair man said wth the cap off for a vent when the bottom hose is removed it should completely drain in a few seconds?

Did not check the bore, verified the ridge, there was none, checked for any wall or piston top damage, there was not any.

I did not time how fast the coolant poured out the bottom hose, but a lot came out quite fast.

Exactly how do you test a block & head for coolant flow when the engine is installed and the pump is off?

Correction, the chain cover does have the two passages for the main flow to the block, the ones on the LA cover I used are open, the LA and Magnum engine blocks have those passages in exactly the same location.

Once the pump is off, just jam a garden hose in one opening and let it rip or if you have a hose with the metal threads removed would be better. You can plug the bypass hose so water is forced through the block in each direction. Then plug the pump openings and force water thru the bypass hose and out block drains, or core plug back and front..... I'd be tempted to pull freeze plugs one at a time and flush/ backflush every which direction possible, and then replace the plugs with brass ones, extra work but it would cover it all.

You mentioned the timing cover was replaced, did you verify top dead center of #1 piston with the balancer mark and "0" on the cover?

Yes, verified engine TDC in relation to chain cover "0" to new balancer "0"

I have a hard time believing the block or a head is plugged with something. The engine being so good, you checked all the passages thru the head gasket were there. Block isn't cracked according to the test. My gut is telling me it's got to be something wrong with the water pump. You've been very diligent. It's got to be something

I can't wait to hear what you figure out in the end. We're chomping at the bit out here  lol

Obtained one of those Borosilicate glass coolant tubes, pretty cool, rather pricey for 6" of hollow glass, a $2.50 used upper radiator hose at Pull-a-Part made up for it, beats chopping up a perfectly good new hose. Also bought one of those fancy never spill funnels, at least it works.

Here are the two devises installed.


The funnel allows for the coolant system to self fill, burp, expel air, belch a little more and when done take on a full load of coolant. In the end when the thermostat opened there was perfect flow, no gaps, no air bubbles, could not get a picture of it, you can see the fluid flow but not capture with a camera, hit the accelerator and the flow increased. What else increased was the temperature, still getting hot, at least i know all the parts are doing what they are suppose to.

I am done, called my insurance company today decreased the coverage to "Vehicle Storage" only, the van is going to the barn probably for the rest of its natural life, or mine, I have built a lot of cars in the last 46 years but never encountered the reincarnation of Christine. Giving up, not exactly, but it is one week shy of four years since obtaining this van, two years behind getting it on the road, cash out lay $16,461.88 with receipts and hundred of hours of labor. Maybe someday I will tackle it again, maybe just pay a wrecking yard to crush it, that would be satisfaction.

I do appreciate all the assistance and ideas from the members here, I will still be lurking for since having a 62 Econoline in the early seventies I have always liked vans. Maybe there will be a revelation one of these years that or I will hire a exorcist and the Dodge can come out of the barn.

I know it's not the right thing to do but if you let it run indefinitely will it boil over? Maybe it's like some people. Hot blooded?

Yes, twice, gauge showed closer to 230*, once without a catch can, the other with it, filled that sucker then spit out the rest. Since then all testing I shut down at 220*. With a 180* & 195* thermostat makes no difference, just how long till the coolant hits the shut down number.

Not sure about the van being hot blooded, but now the idea of working on it does it to me.

I know your fed up and I don't blame you. I re read your original post. Is the radiatiator new? Do you have access to another known good radiator in a van that's running a v8? I'm gonna ask a couple of my friends that I consider ace mechanics for any other ideas

Yes the radiator is a new FSR, no do not have access to another and right now, would have to buy one which is not high on my list of things to do.

busman78 wrote:Yes the radiator is a new FSR, no do not have access to another and right now, would have to buy one which is not high on my list of things to do.

I can't imagine what the problem could possibly be.

I'm sorry that you will be putting the van in storage but I feel your frustration, sometimes it is best to walk away for a while. You may get a second wind and want to have another go at it. Or something's aren't meant to be and it may best to move on.

Either way best of luck...

Just curious if you revved it up any with the funnel still in and if it would fill the funnel back up ?

Exhaust all new pipe? No chance of an inner wall folded up restricting the flow?

All new pipe, glass packs and ceramic coated manifolds.

With the blown head gasket previously and now everything has been replaced and is new and checked yet still runs hot I'd say it's something within the block, intake cross over or head passages. That's all it can be in my summation. Everything has been verified: Water pump, thermostat, hoses, radiator, gaskets, coolant, cap and correct psi, flow at the radiator, intake manifold water passage crossover? block passages, head passages,  bypass hose? The engine is building too much heat because the coolant is not circulating within the block/heads.

When rpm's increased with funnel attached the fluid rises then drops as the rpm's lower

The heads were just cleaned, checked and milled. I have drained the block twice, both times pretty close to equal amounts of green fluid poured out the drain plugs, no rust. The intake is a new Edelbrock Air Gap. The new head gaskets were FelPro 9898PT which have exactly the same openings as the factory original.

Now I would of preferred using the Mopar Performance head gasket but it had not been available since early last year, benefit being a closer to bore diameter and a tad thinner when compressed. Finally the Dodge dealer nearby got my back order in, hot diggity dog, package had the Mopar Performance part number on the outside, the gasket inside was the stock 360 gasket fresh from the plant in Mexico, what a let down.

busman78 wrote:When rpm's increased with funnel attached the fluid rises then drops as the rpm's lower

Im no expert but Ive filled a few radiators, doesn't that seem backwards?

Wouldn't the pump draw it down at high rpms and let it fill the rad back up at idle?

Just trying to help...I really want you to fix this thing!

Yea except the whole system is full, maxed, non pressurized system so when rpm's increase the flow pushes fluid up some into that funnel, not a lot, looking at 1/4" maybe a little more. Leave the cap off your radiator fill it to the rim let it get hot then kick the accelerator and you will most likely have fluid push out. Not a lot but it will make a mess. Out the opening is easier than through the system, path of least resistance.

Now on shut down the heat expansion fills the funnel with 3"-4" of hot coolant, then when it cools sucks it back in, right now the radiator is full to the cap, next time it runs that extra coolant when heated up will discharge to the catch can. It is a vicious cycle.