4d56 overheating w/ A/C on on traffic

[miked]

Symptom: overheating (>212F & <220F) with the A/C operating on traffic
Engine: 4D56 turbo
Trans: A/T internally cooled by engine radiator

Previous R&M done:
1. Head Gasket replacement (5 months ago)
2. Installed 82C thermostat (last feb 2011)
3. Changed to SAE 15W-40 engine oil (2 weeks ago)
4. Valve clearance adjustment (0.25 mm) 2 weeks ago also

Other inspected parts:
1. Coolant level ok. No leaks and doesn't consume coolant. I usually recycle the coolant at the reservoir back to radiator. For the past 5 months, I approximately consumed 1.5 liters of water.
2. Upper hose not hard as a rock
3. Lower hose not soft as a sponge
4. V-belt tension ok
5. Water pump not weeping coolant via weep hole. water also circulates as per inspection at the rad neck
6. No binding brakes
7. No cross-contamination of engine oil, coolant and AT fluid
8. Bubbles about half an inch to 1 inch come out of the rad neck in intervals of about 5 seconds or more even at operating temp. Coolant level rises up at rad neck
9. Exhaust smoke colorless at idle
10. Cools down after constant high revs at idle, highway runs, or with the hood open and sometimes after splashing water at the A/C condenser (note: not the engine radiator)
11. With the hood closed, temp climbs =>212F with the A/C on but stays in between 180F & 200F with the hood open.

My gut tells me that its an airflow problem and the headbolts coming loose again. I just did the head gasket job 5,000 km ago.

Please help guys. thanks

[miked]

Before i installed the thermostat, it overcools on highways and overheats on traffic.

Now it is thermostat equiped it stays at 180F before open driving then stays between 180F & 200F on open driving. the problem starts on traffic. with the aircon on, it rises faster. with the aircon off, it doesnt rise that much. both situation with hood closed. i have this feeling that tells me an airflow problem.

[rmpmla]

sir, have you check the radiator clutch fan?

baka kailangan ng silicon oil refill.

[reym]

Hi SIr Miked,

Have you checked if your head is warp free?

[Dieseldude]

Look at the temp setting of thermostat. Opening temp is normally stamped on the thermostat. It will open at that setting.

[utk505]

Check fan clutch , if ok , remove radiator clean radiator fin and also the condenser fins if still overhears may problem sa engine

[dvldoc]

A very simple Tstat modification you can do is to drill it. We do it on a lot of the higher performance cars here in the states, lowers the temps of your car without loosing the function. Sometimes you can't get a stat with the range you want so you can just drill it.

This is particulary common on 180F ones. I have put in a drilled stat on every Grand Prix I have owned including the Daytona 500 one I have now (they are superchared from the factory) It gets to 110F here in south Texas so you need it. Most of the Corvette and Z28 guys do the same thing as well.

Two 1/16" holes should make a nice difference for you and might eliminate your problem. I run a drilled 165F stat in my car. I drilled out the one on my Elgrand as well. It had no stat when I got it which I don't like so I replaced it. Never gets overheated no matter how I pound on it.

[gmd]

Good day to u,ito lang ang masabi ko ang thermostat mo dapat 75c at ang iyong auto- fans clucth ay kailanga ma check o palitan na,check mo din ang a/c fins air flow & radiator, bleeding cooling water system...

[marz]

sir, have you check the radiator clutch fan?

baka kailangan ng silicon oil refill.

+1 ako dito, malamang yan ang solution sa problem mo.

[miked]

sir, have you check the radiator clutch fan?

baka kailangan ng silicon oil refill.

i refilled it about 6 months ago i think. doesn't free wheel when engine stopped....if ever the silicon content is good. i'm thinking na yung bimetallic strip ang may defect.

Hi SIr Miked,

Have you checked if your head is warp free?

as per inspection las head gasket change, the head is still good.

Look at the temp setting of thermostat. Opening temp is normally stamped on the thermostat. It will open at that setting.

82C as indicated on my first post.

A very simple Tstat modification you can do is to drill it. We do it on a lot of the higher performance cars here in the states, lowers the temps of your car without loosing the function. Sometimes you can't get a stat with the range you want so you can just drill it.

This is particulary common on 180F ones. I have put in a drilled stat on every Grand Prix I have owned including the Daytona 500 one I have now (they are superchared from the factory) It gets to 110F here in south Texas so you need it. Most of the Corvette and Z28 guys do the same thing as well.

Two 1/16" holes should make a nice difference for you and might eliminate your problem. I run a drilled 165F stat in my car. I drilled out the one on my Elgrand as well. It had no stat when I got it which I don't like so I replaced it. Never gets overheated no matter how I pound on it.

been thinking this one. read it from a motor mag but what part of the tstat should be drilled with respect to the bridge?....


road trip kami kahapon here sa province. from 1130-230, even on highway with the A/C on, the temp climbs to 212 and higher. pero when i put off the A/C, bumababa na.

then 3pm onwards stayed at 200F and sometimes lower with A/C on pa rin.

yun nga lang pagdating sa bahay, iniwan ko na naka on ang A/C while letting the engine cool off with the hood closed- ayun umakyat uli sa 212F. i switched off A/C and opened hood and some high rpm ayun bumaba naman...something like a cyclic overheating is happening and i don't know why..take note halos high revs ang ginawa ko just to test my hypothesis......

can't afford to sacrifice the comfort of having an A/C esp summer with my kid on the road.

i'll tinker with it this weekend. buti na lang dinala ko tool set ko.

[phezthie]

hey bro, yung a/c ba na check mo na kung hindi nag hi-high pressure?... pwede din kasi iyon ang cause...pag high pressure, mas mahirapan fan mo palamigin yung rad and condenser..

[Ry_Tower]

Usually sa ganyan mahina na yung rad fan or yun nga ^ high-pressure yung a/c mo!

[miked]

plus another culprit is the A/T could be overheating also contributing to the cyclic reading on the gage. my plan is to put an external cooler and bypass the internal cooler...hirap nga lang maghanap lalu na andito nako province for a vacation.

[dvldoc]

i refilled it about 6 months ago i think. doesn't free wheel when engine stopped....if ever the silicon content is good. i'm thinking na yung bimetallic strip ang may defect.

as per inspection las head gasket change, the head is still good.

82C as indicated on my first post.

been thinking this one. read it from a motor mag but what part of the tstat should be drilled with respect to the bridge?....


road trip kami kahapon here sa province. from 1130-230, even on highway with the A/C on, the temp climbs to 212 and higher. pero when i put off the A/C, bumababa na.

then 3pm onwards stayed at 200F and sometimes lower with A/C on pa rin.

yun nga lang pagdating sa bahay, iniwan ko na naka on ang A/C while letting the engine cool off with the hood closed- ayun umakyat uli sa 212F. i switched off A/C and opened hood and some high rpm ayun bumaba naman...something like a cyclic overheating is happening and i don't know why..take note halos high revs ang ginawa ko just to test my hypothesis......

can't afford to sacrifice the comfort of having an A/C esp summer with my kid on the road.

i'll tinker with it this weekend. buti na lang dinala ko tool set ko.

You would drill opposite the bridge on the T-stat.

[tip_tipid]

you've got a coolant flow problem. ewither the thermostat does not open wide, or the waterpump fins have corroded.

[niwde11]

kung pag aC at traffic lang de AC nga me problema. usual is high pressure or lack or ram air(mahina yung aux fan ng condeser)

[miked]

hey bro, yung a/c ba na check mo na kung hindi nag hi-high pressure?... pwede din kasi iyon ang cause...pag high pressure, mas mahirapan fan mo palamigin yung rad and condenser..

actually, electric fan equipped din pipip ko. wired with the A/C circuit.....i'll have it checked then after i check the fan clutch.....

quick question: should the fan clutch turn lighter when turned by hand when hot than when cold? this is the situation right now.

and the temperature readings are based on a mechanical gage. actually i also have the electric stock gage working but the mechanical is more sensitive to changes....nasa 140F na yung mechanical, yung electric gage nasa Cold line pa lang. saka lang pupunta sa gitna ng 1st and 2nd line after say 15 minutes that is at 180F. but at times, the stock electric is about in excess of a hairline above the 2nd line when the mechanical gage reads >212F.

[miked]

kung pag aC at traffic lang de AC nga me problema. usual is high pressure or lack or ram air(mahina yung aux fan ng condeser)

sir
as i've said in my previous post, it also occurred at high speed driving (w/ A/C on) especially on the hottest time (11AM-2PM)........

[phezthie]

actually, electric fan equipped din pipip ko. wired with the A/C circuit.....i'll have it checked then after i check the fan clutch.....

quick question: should the fan clutch turn lighter when turned by hand when hot than when cold? this is the situation right now.

and the temperature readings are based on a mechanical gage. actually i also have the electric stock gage working but the mechanical is more sensitive to changes....nasa 140F na yung mechanical, yung electric gage nasa Cold line pa lang. saka lang pupunta sa gitna ng 1st and 2nd line after say 15 minutes that is at 180F. but at times, the stock electric is about in excess of a hairline above the 2nd line when the mechanical gage reads >212F.

mate, ano klase ba yung fan mo, bi-metallic strip and control piston or yung bi-metal spring connected to an opening plate? meron din Flex-Fan..

if your condenser fan is in good working condition i would suggest to check your rad fan for possible trouble...

run the engine at a fast idle speed until normal operating temperature is reached. stop the engine and immediately check the effort required to turn the fan (take due care, use gloves). if considerable effort is required, it can be assumed that the coupling is operating satisfactorily but if very little effort is required to turn the fan, it is an indication that the coupling is not operating properly and should be replaced.

if the clutch fan is the coiled bi-metal spring type, it may be tested while the vehicle is being driven by disconnecting the bi-metal spring, and rotate it 90 degrees counterclockwise to disable the temperature-controlled free-wheeling feature and the clutch performs like a conventional fan. if this cures the overheating condition, replace the clutch fan.

here's the link on how to recondition the clutch fan http://zhome.com/ZCMnL/tech/FanClutch/FanClutch.htm

[phezthie]

BTW there are some techs who do not recommend reconditioning... they prefer and recommend replacement...FYI...

hope you solve your car's problem soon, regards..