HOW TO TEST FOR A FAILED HEAD GASKET

bibs_and_bobs_r_us
By Published by
HOW TO TEST FOR A FAILED HEAD GASKET
. Views . Comments Comment . 2,230 Votes

 

EFFECTS OF A FAILED OR "BLOWN" HEAD GASKET

THE FAILURE OF THE HEAD GASKET WILL LEAD TO OVERHEATING PROBLEMS, BOILING UP AND PRESSURISATION OF THE COOLING SYSTEM THAT CAN LEAD TO THE FAILURE OF THE RADIATOR, HOSES OR EVEN THE EXPANSION TANK CAN EXPLODE, OIL AND WATER CONTAMINATION, CRACK TO APPEAR WITHIN THE CYLINDER HEAD, POOR PERFORMANCE, UNEVEN RUNNING AND EVENTUAL CATASTROPHIC ENGINE FAILURE IF USED FOR A PROLONGED PERIOD A OVERHEAT TEMPERATURE.

WHAT ARE THE TELL TALE SIGNS?

BY FOLLOWING THIS PROCEDURE YOU WILL BE ABLE TO IDENTIFY A FAILED HEAD GASKET.

1. OPEN THE BONNET AND WHITH THE ENGINE COLD CHECK THE COOLANT LEVEL AND COLOUR. IT SHOULD BE AT THE NORMAL LEVEL AND THE COOLANT SHOULD BE EITHER CLEAR OR BLUE OR GREEN COLOURED BY THE ANTI FREEZE, IT SHOULD STILL BE CLEAN AND CLEAR, THE INTERIOR OF THE EXPANSION TANK OR RADIATOR SHOULD ALSO BE CLEAN WITHOUT ANY SIGNS OF A SOAPY THICK CREAMY DEPOSIT. IF THERE IS A THICK CREAMY SCUM THEN THIS IS A GOOD INDICATION OF WATER AND OIL CONTAMINATION AND THE MOST COMMON CAUSE IS HEAD GASKET FAILURE OR A CRACKED CYLINDER HEAD. IF ALL IS AS IT SHOULD BE MOVE ONTO CHECK 2.

2. TAKE OUT THE OIL DIPSTICK, AND LOOK AT THE OIL ATTACHED TO IT IT SHOULD BE CLEAR OR BLACK, IF IT IS A CREAMY COLOUR  THEN THIS INDICATES THAT WATER HAS MIXED WITH THE OIL AND THE MOST COMMON CAUSE IS A FAILED HEAD GASKET OR CRACK IN THE CYLINDER HEAD. IF THE OIL IS CLEAR OR BLACK MOVE ONTO CHECK LIST 3.

3. REMOVE THE CAP TO THE EXPANSION TANK AND START THE ENGINE, ALLOW THE ENGINE TO RUN UP TO NORMAL TEMPERATURE WATCHING THAT THE WATER LEVEL REMAINS CONTANT AND IS ROTATING AS IT SHOULD, REPLACE THE CAP TO THE EXPANSION TANK AND LEAVE THE ENGINE RUNNING, IF THE VEHICLE IS FITTED WITH AN ELECTRIC COOLING FAN ALLOW IT TO CYCLE ON AND OFF ON ITS OWN AND MAKE REGULAR CHECK ON THE TEMPERATURE GUAGE IT SHOULD SIT AT NORMAL SWITCH THE INTERIOR HEATER TO HOT AND TURN ON THE INTERIOR FAN THE HEATER SHOULD BLOW WARM OR HOT IF AFTER RUNNING AT NORMAL TEMPERATURE FOR 10 MINS THE GUAGE HAS STAYED AT NORMAL, THE COOLING FAN HAS CYCLED ON AND OFF PROPERLY AND THE INTERIOR HEATER IS STILL BLOWING HOT ON DEMAND TURN OFF THE ENGINE AND GO TO STEP 4.

4. ALLOW THE ENGINE TO REST FOR A COUPLE OF MINS, THEN WITH GREAT CARE AND WHILE WEARING GLOVES TO PROTECT YOU FROM THE HEAT TRY SQEEZING THE TOP HOSE FROM THE RADIATOR,  IF THE HOSE IS SOLID THEN LEAVE A LITTLE LONGER UNTIL YOU CAN SQUEEZE IT A LITTLE THEN  SLOWLY REMOVE THE CAP TO THE EXPANSION TANK OR RADIATOR, IF THE GASKET OR CYLINDER HEAD HAS FAILED THERE WILL BE A GREAT GUSHING OF BOILING WATER SO YOU MUST DO THIS CAREFULLY. STAND WELL BACK AND RELEASE THE PRESSURE SLOWLY, IF THERE IS NO GREAT GUSH A SLIGHT HISS, LIKE OPENING A POP BOTTLE  IS OK BUT DO NOT BE TEMPTED TO DIP YOUR FINGER IN IT IT IS STILL VERY HOT. NOW CHECK THE OIL AGAIN AND THE COOLANT FOR CLARITY IF THEOIL IS CLEAR AND NOT CREAMY COLOURED AND THE WATER IS CLEAR AND THE ENGINE TEMPERATURE WAS STABLE AND NORMAL THEN THE LIKELYHOOD IS THAT EVERYTHING HEAD GASKET WISE IS TICKETY BOO.

THE SHORT VERSION

IF THE OIL IS CREAMY COLOURED AND THERE ARE SOAP LIKE DEPOSITS IN THE ROCKER COVER WALK AWAY.

IF THE CAR OVER HEATS FOR NO APPARANT REASON WALK AWAY

IF THE WATER IS CONTAMINATED WITH OIL OR A SOAPY SUBSTANCE WALK AWAY

IF THE COOLING SYSTEM PRESSURISES ABNORMALLY WALK AWAY.

IF THE TEMPERATURE GAUGE DOES NOT WORK, IF THE CAP IS MISSING OFF THE RADIATOR OR THE EXPANSION TANK, IF THERE ARE SIGNS OF SOAPY DEPOSITS OR EVEN WORSE FRESH WIPE MARKS INSIDE THE OIL FILLER CAP OR EXPANSION TANK, ANY SPLITS IN THE RAIATOR OR EXPANSION TANK THEN WALK AWAY AS THE LIKELIHOOD IS THAT THE GASKET HAS FAILED AND CAUSED THE SUPPLEMENTARY PROBLEMS ABOVE.

CAN IT BE REPAIRED.

THE SHORT ANSWER IS YES, BUT THIS IS NOT A CHEAP JOB, A COMPETENT DIY MECHANIC COULD SAVE THEM SELF THE LABOUR COST BUT MY ADVICE IS GET A RESPECTABLE GARAGE TO DO THE JOB AND GUARANTEE THIER WORK.

THE REPAIR WILL USUALLY INVOLVE THE PURCHASE OF A GASKET KIT AND CYLINDER HEAD BOLTS AS THESE ARE MADE TO STRETCH AND SHOULD ONLY BE TORQUED DOWN ONCE.

THE CYLINDER HEAD WILL NEED TO BE SENT  TO A SPECIALIST FOR PRESSURE TESTING AND SKIMMING FLAT TO TAKE OUT ANY WARPS CAUSED BY THE EXESSIVE TEMPERATURES.

THE TYPICAL COST OF THIS REPAIR FOR A STANDARD 4 CYLINDER CAR WOULD BE

GASKET KIT AND REPLACEMENT BOLTS £75.00

HEAD TESTING AND SKIMMING £75.00

6 HOURS LABOUR AT £30 = £180.00

CONSUMABLES OIL, FILTER, ANTIFREEZE ETC £40.00

SO A TYPICAL HEAD GASKET FAILURE COULD BA AS LITTLE AS £370.00 PROVIDING THE HEAD HAS NOT CRACKED.

IF THE HEAD HAS CRACKED THEN IN ADDITION TO THE ABOVE YOU WOULD NEED TO SOURCE AND PAY FOR A REPLACEMENT HEAD.

I HOPE THAT AS A PROSPECTIVE BUYER YOU FIND THIS GUIDE USEFUL, YOU CAN USE THE RESULTS OF THIS TEST TO DECIDE WHETHER TO BUY OR NOT OR TO NEGOTIATE A PRICE THAT REFLECTS THE CONDITION, DO NOT RISK DRIVING IT HOME IF YOU CAN POSSIBLY AVOID IT GET IT TOWED OR RECOVERED TO WHERE THE WORK CAN BE DONE.

IF THIS HAS HELPED YOU PLEASE LEAVE FEEDBACK FOR IT

Choose a template