Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Bulldog67]

Im prepared to sling wads to get this MOFO sorted or CF will be done this year in a frickin dulvo

The Chief STILL overheats, despite a new engine and twin elec fan set up. Weird thing is it doesn't do it from start up.  Drove bout 25 miles today on way to the play day b4 it decided it was unhappy, last 20 miles of which was m/way. It just hovered near the 'oh shit' area.

No probs at the off road site - stayed in the middle zone.

Then on the way home it hits the hot spot and goes beyond - I had a theory that the temp sender was fooked so ignored it and drove about 10 miles like that but once I got home I could see that there was steam coming from the overflow bottle.

I had drained it and flushed it via every god-damn pipe on Friday and it runs clear water. I then did the coolant at 50/50.

So much of this truck is awesome but this is pissing me off.

Its been running hotter (via the temp guage) than normal since I got it back but before the aborted Harptree journey it had done a 250 mile trip to Billing without any issue

Shall I just get some super core bastard rad?

Tues Im planning on ringing lightys for a new sender and thermostat but other than that sling as many ideas as poss please gents coz this has to be sorted.

[bigjeepzj]

Are you sure your fans are kicking in
what controller are you using

[Bulldog67]

if i switch it off then I can hear the fans

and when Im tootling around town etc it gets hot ish and then suddenly comes down as (I assume) the fans kick in

it did occur to me that maybe they kick in too late for m/way driving?

[wildwood]

Had a BMW that overheated after a while......on m ways........specifically in the south of effin France.......

Vacuum advance and retard had a perforated pipe that meant engine ran too advanced and overheated.......new length of pipe and was sorted as a sorted thing........

Don't know if your manly 401 and it's HEI have vacuum advance retard but..........just my 2 cents.

[dtooth]

does your gearbox have a cooler in the rad like the xj do . i had it where the gearbox was causing the jeep to overheat on the motorway turned out to be a block oil cooler

[wildwood]

If you have any spare coin......
Worth having separate trans cooler with own fan......Summit do em......
And if you are really anal two gauges ........one measuring fluid in and one fluid out.....
Overheated auto boxes just don't deliver the goods.....


Now......how do I know that

[ferretjuggler]

I'm thinking ignition timing or too weak fuel mixture at small throttle openings.
What ignition system are you running?

[Cockney Boy]

Is your fan wired around the right way? And what speed were you doing on the motorway?

[bigjeepzj]

good point

[Bulldog67]

It's Hei dizzy. Carb is sooty - was sooty after American muscle 'expert' tuned it and it's still sooty - does that mean owt in connection to overheating?

What would carb look like if engine ran too advanced?

I believe the gearbox is cooled via the rad - how do I check for blocked oil cooler?

Jim (sunderland4x4) did the fan so im guessing it's correctly wired.

And speed was a genuine 50-65mph max - im still running it in so not caning it. I have tried running slower or faster once its hot but it changes nowt.

[ferretjuggler]

If the transmission cooler in the rad was blocked,  the trans would be getting too hot but the rad would not.

Easy to check out.
Disconnect the pipes and GENTLY blow it through with a very low pressure.
Might be worth rigging up temp sensors in the inlet and outlet so you can find out exactly what is going on.

[bigjeepzj]

the fact that you do not have a separate cooler may be you problem
the auto box is over heating your rad

[bluevanman]

if it overheats at motorway speeds it deffo wont be the fans they cease to be effective above about 35ish mph

[Nosebolt]

lets get this right it only overheats when moving at 'speed' not off roading?

if so a couple of things come to mind, mixture and timing as mentioned and I would also check if the body/winch/bumper mods have changed the airflow, it is possible to create a high pressure area behind the rad that can cancel out the fan, this would only happen at speed.

[Bubba]

here is a dumb one for you are you sure the bottom hose is good ? i spent about six weeks fretting about all sorts of problems on a chief i owned with exactly your symptoms

i eventually discovered just before tearing down for head work that at just over half revs the bottom hose slowly sucked itself flat closing the flow off and overheating and opening when returned to tickover

the reinforcing spring had rotted and collapsed new hose no problem   

[bigjeepzj]

Good point

[dtooth]

options for oil cooler

http://www.ebay.co.uk/itm/30-rows-High-Performance-Transmission-Engine-Aluminum-Oil-Cooler-Silver-Fan-/261150376716?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item3ccdc6830c#ht_3674wt_1001

[Bulldog67]

Ok I suppose cheapest first:

bang it up to overheating and check the bottom hose isnt collapsing

if it isnt ....

then take the winch off and see what happens ....

makes sense?

[Bulldog67]

options for oil cooler

http://www.ebay.co.uk/itm/30-rows-High-Performance-Transmission-Engine-Aluminum-Oil-Cooler-Silver-Fan-/261150376716?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item3ccdc6830c#ht_3674wt_1001

cheers dood 

price is right

is it easy (ie not £££sss) to fit?

[JamesH]

All sounds like sensible ideas, is it a TH400? I've heard they can get a bit warm so separate cooler is definitely a  good idea and will only help temps. Oil cooler isn't too hard to fix, just needs to be mounted and connected up - will need more fluid after fitting too. Bottom hose problem happens on XJs too, check the price of a replacement, if it's not stupid just change it, there's not really a negative to having new hoses.

Sent from my MZ604 using Tapatalk

[Bulldog67]

Yup TH400 - bottom hose looks good but gotta ring lightys 2mrw anyway

[dtooth]

read though some useful info and its uk based
http://www.rodsnsods.co.uk/forum/stuff-wanted/th400-oil-cooler-fittings-52047

[Mike Pavelin]

Clagged up rad core? Internally, not mud on the outside.

[Bulldog67]

Luckily that is one i can def discount - when Jim did the 401 he had to spend 30 mins clearing all the mud out of the rad once he had taken it off

[Dave69]

first thing you really need to measure the temperature of the coolant going into the radiator and coming out. the bigger the number difference between the two means the radiator is working effectively. if the number is small then the radiator is not working due to the lack of airflow.
 with the gearbox cooler running in the radiator is not something new and it is a very effective way of keeping the gearbox matched to the running temp of the engine.

with the new fans fitted what temperature have you set for them to operate, if its 100 then quite possibly you might need to drop the setting to 95 and see how that runs.

running at slow speeds the temperature is acceptable but at motorway it over heats. Normally this should be fine as the air is forced through the rad into the engine bay. possible lack of flow out of the bay might be an issue or there is no suitable shroud around the cooling fans. Taking into light what Nosebolt mentioned if the shroud is not adequate what could be happening is that you are creating a low pressure in front of the car which is then pulling the hot air from the engine bay and pushing it back again through the rad which in turn starts to "superheat" the all ready hot air. Seen this happen.

Rather than throw money review the setup you have around the rad, maybe use some card to improve the existing fan shroud. But personally i would see what happens with the temperatures going in and out of the rad during motorway running.

if you have a collapsed support spring in the lower hose as Bubba has indicated then slide inside a plastic support, an empty mastic tube body cut to length will provide adequate support.