getting hot

[p.p.]

my "rhowina" getting hot when i drive up hills, with ca. 300 kilo load, outside temp. 23° celsius.... i now she is not made for mountains- but hills 3 miles up and she is 100 ° celsius , on the top mark... is that normal

shall i put a extra water tank in the back to get her extra water (10-15 liter) with a tap to open if i get to a hill or mountain...
peter

[Keith Andrews]

Running hot..
Generally the 1st and most simple check is HC traces in the radiator...and reputable workshop will check in less than 5 min and usually a free service...this eliminates cracked heads/head gaskets etc
If the coolng system has had regular maintance as it should, and the cores manually cleaned last engine rebuild....thermostast..check in a jug of water and thermometer
Temp gauge....again check gauge is reading correct in the a jug of water and confirm reads correct.

Going up hills I assume these are low hills not getting up into the snow lines..when one gets up into the snow lines the rarefided air leans the mixture out making the engine run warmer than normal....If one generally lives in these areas tuning for a richer mixture is the norm.

When was the last time the radiator was manually cleaned with the header tanks off? most common cause of running hot.
An engine, inspite of common belelf is not effected by ambiant temps...if it is then either cores are blocked/restricted and/or the cooling fins have deteriated away to the extent there is little heat transfer

Anther issue that occassional occurs is when the raditor is being put in, they decide to give it a new coat of paint...a nice heavy coat of enamel or whatever.....instead of the black paint increasing heat disapation it retains.....raditors should only have a thin caot of a matt black....water based tyre black is ideal.

[p.p.]

thank you keith,

890 miles ago the radiator was cleaned completly, was not paintet... is still black, very tin paint.
the temp. gauge is reading correct, was checked.
the hill was not in the snow line just from 600-1100 meter.
the engine was not rebuild but the cores was clean, the cooling water running throu the engine, no problem.
the cooling fins on the radiator ar in 60-70% good condition.
on flat road speding 60 miles ar no problem temp. reading 75° celsius.

peter

[Keith Andrews]

Only going up hill O?K at idle?
Everything else ok then...
you havnt polishe or chromed tappet covers sumps etc?

Then i would say you could be leaning out a little under light load and or not enough advance at that point t in the cent curve...
Have u checked with timintg light the idle advance and the mid and total (idle +cent advance) are all in at the correct rpms?

[Jack]

What type of radiator have you got? Thin wire type or more open finned honeycomb type?

Against common sense, the one with the bigger gaps (and less fins) seems to provide more cooling, the air can flow through it better so it cools more.

Keith C had quite a few problems with overheating, we swapped his wire type to the honeycomb type from my car (which hadn't been professionally cleaned or anything, just took it out and swapped it I think, it was probably flushed through a couple of times) and the problems miraculously disappeared.

Jack.

[p.p.]

hi jack,
will send you a pic of the radiator, so you get a good ideea of the typ.
thanks for the help...

peter

[Robin Fairservice]

Does your car still have the shrouds on each side of the radiator? If not, then air is not going through the radiator, but passed it and out of the vents. On long hills do you stay in top gear? If you change down to third, the engine revs are higher and the fan is turning faster.

[p.p.]

shrouds on each side of the radiator please exlain me , im not the best mechanic....

yes i change to 3. and also if it gets steeper to 2. gear to get the rev up...

i send jack same pic via handy( name in switzerland) mobilphone, hope it will show the radiato type. i think it is the honeycomb type.

peter

[Robin Fairservice]

The shrouds are pieces of sheet steel that are fixed to the body and fill in the space between the body and the radiator. I can't find them listed in the Parts Manual. I could take a picture of mine if necessary.

[Keith Andrews]

the engine revs are higher and the fan is turning faster.

Once over about 30 mph the amount of air that goes thru the radirator is so great one doesnt need a fan...the amount the fan moves is insignificant.
Shrouds..these a majic things...improve air flow up in the 80% range
Run a Chev without a shroud at low speed and it will not run hot, it will over heat.
Notice the cooling fans in your computer are shrouded yet these little fans move a huge amount of air with little effort.
A Shroud stops the centfial action of spilling air off the ends of the blades.
But all this has no effect above 30 mph.
I still come back to
1/the raditor has blocked cores
2/incorrect jetting..which mentioned above altitude does have a huge effect...If it is slightly lean nothing noticed under normal load, but slight load is enough to cause hotter runing
3/Incorect timing for the fuel type.
It is rare on old cars that onlt 1 thing is at fault, thu we do wish it was....I suggest a couple blocked cores and slightly lean combo....each , say fix cores maybe enough to hide the slightly lean comdition.

[Tony Fearn]

Hello Peter.

Although you say that the radiator and engine water chambers are ok, I wonder if such a simple thing like using a radiator flush compound might just find some more rubbish in the system which you can flush out.

But don't forget the antifreeze afterwards, especially if using Rhowina above the snow line!

Tony.

[Forumadmin]

Search on overheating' on JowettTalk and you will find many posts.
The weather is unusually hot, so the first question is have you driven up that hill when it was the same outside temperature? Is it a new problem?
You say you have driven at 60 mph with no problems. Try driving at 65 to 70mph or flat out for at least 10km and see if the temperature rises. This will see if it is load related, rather than air flow or speed (the same amount of heat should be generated by the engine as in hill climbing but with greater air flow).
The most likely cause is water flow through the radiator, followed by the distributor timing (either too advanced caused by wear in the max advance stop, or retarded due to advance not working to the proper advance curve). I have assumed you have set up statically on TDC, so check speed advance works with a timing light (2500rpm should be 22 degrees advance). Suck on vacuum advance and see if it moves the plate! First check the number of the distributor corresponds to a Jowett type (search JowettTalk http://jowett.net/forum/viewtopic.php?f ... rve#p10065), then make sure the weights and springs are all functioning and the advance stop has 10deg stamped on it. As KA says head gasket leak is a possibility so a CO or Hydrocarbon check of the water is quick to rule that out. Small 'air' bubbles in the top of rad are a sure sign of that problem. Some Australian guys who have to cope with high ambient temps reckon that 5 rows of tubes in the rad and a modern narrow gap between the cooling fins on the rad is not good. 3 rows and wide fin spacing is better. I also think that modern cores have tubes that are smaller diameter which easily get clogged with the sludge of the Jowett alluminium block. Back flushing and soaking in a central heating descaler should help.

[Keith Andrews]

Discussed this today at our Club Garage crawl..One of the members commented that he had his radiator headers pulled . cores cleaned and still noticed between hot summer cold winter anout 5/7 degs diff with difference in ambiant temps.
It is also noted that this is a well tuned engine which has regularly pulled prizes in the economy runs...
IF this engine is close on lean with little margin....it is very likely the issue is not ambiant temp but less O2 because of the ambiant temp and running on the line with mixtures.

Further th KC above, if that dizzy is not swinging out you will also definately notice a huge lack i power and excessive fuel comsumption....the margin between run go and guttless is only 2 to 3 degs at any given rpm.

[p.p.]

its a pitty nowbody from the jowett family is in switzerland near my place.....the mebers of knowledge ar far away.... but lot of good suggestion for my problem i realy like it, very helpfull

i dit soaking and flushing with a descaler solution, 615 miles ago....got all the sludge out maybe i have to do it again
just about the fuel consumtion: for 615 miles i need 23.8 imp.gallon // 1014 km - 108.5 liter gasolin 95 oktan -- 3.87 imp.gallon for 100 miles // 10.66 l for 100 km. on the heavy side, the power ar good
on 20 km trip, flat road / 17° celsius / speed betwin 30 miles and 60 miles,the temp. ar below 75° celsius !
on neutral the idel is high.
will in the next days, when the weather is good, to make a 20 km run with 70 mile....will see wath happens...

thanks for keith a, keith admin, tony,robin and jack for help a bundu jowett with a problem feel like in a big famly

peter

[Keith Andrews]

26 mph thats what one would get from a modern fuel injected ECU controlled Buik 3.8L car...If ganny footed on the open road....vauxeul or holden.
Or put another way normal driving in a well tuned /set up 40yr old carburetted 5.7L 3300lb American muscle car.

Do you have any play, checking in 2 directions in the butterfly bushes on the carb?
is the idle and mixture screws within +/- 1/2 turn off 1 1/2 turns out?
Check that dizzy as KC suggests to

And do not count on an engine flush to unblock radiator cores.. yes it cleans out scale and sludge etc, but it cant get past a plugged up core to clean that up.