Leak detection, pressure testing, soldering and TIG welding repair for copper-brass and aluminium diesel generator radiators from 125 KVA to 1200 KVA. All major brands. Fast turnaround. Pickup & delivery across Mumbai. 6-month warranty on all repair work.
A leaking DG set radiator is not just an inconvenience — it is a warning sign that your generator engine is at serious risk. Coolant loss leads to engine overheating, which can cause irreversible engine damage in as little as 20–30 minutes of running at operating temperature without sufficient coolant. At Ajanta Radiators, we have been diagnosing and repairing DG set radiator leaks at our Worli, Mumbai workshop since 1970. Fast diagnosis, honest assessment, and a pressure-tested repair with a 6-month warranty.
Step 1: Switch off the DG set immediately — do not run a leaking generator.
Step 2: Let the engine cool fully — at least 30 minutes — before touching the radiator or coolant cap.
Step 3: WhatsApp us a photo of the leak area and your DG set brand and KVA — we respond within the hour with an assessment and pickup arrangement.
Do NOT: add water or top up coolant and continue running — this masks the leak and can cause severe engine damage from diluted coolant or continued loss.
Alt text: "DG set radiator with coolant leak at tank joint — before repair at Ajanta Radiators Worli Mumbai"
Different leaks have different causes and different repair approaches. Here are the most common types we see at our Worli workshop:
The most common DG set radiator leak. The solder joint between the brass top tank and the copper tube header plate cracks from years of thermal cycling — heat expansion and contraction. Common in Kirloskar KG series, Ashok Leyland Leypower, and KOEL iGreen sets. Repaired by re-soldering and pressure testing.
Individual copper tubes inside the core develop cracks or pinholes from corrosion, scale deposit pressure, or age. On copper-brass radiators, individual tube failures are repaired by plugging the failed tube and soldering a new tube alongside. Widespread tube failure indicates a recore is needed.
The inlet and outlet hose fitting joints on the radiator tank develop leaks from vibration and age — common on all brands but particularly Cummins QSB/QSL9 and KOEL iGreen sets. We re-seat, re-solder, or replace the fitting assembly to eliminate the leak permanently.
Bottom tanks crack from accidental impact during DG set maintenance, rough coolant draining, or thermal stress on older sets. We repair bottom tank cracks by soldering or fabricate and replace the full tank in-house at our Worli workshop where damage is too extensive to repair.
Caterpillar and newer Cummins DG sets with aluminium radiators develop multiple pinhole leaks from electrolytic corrosion in Mumbai's coastal environment. We repair by TIG welding for isolated pinholes. Multiple recurring pinholes indicate a copper-brass core upgrade is the better long-term solution. See CAT upgrade →
Cummins K19 and KTA series DG sets are well-known for developing stress cracks at the header plate-to-tank joint from high thermal cycling at large load. We repair header plate cracks by soldering or brazing and pressure test to confirm the joint is fully sealed before returning the radiator.
Coolant overflow from the overflow tank is often misdiagnosed as a radiator leak. The actual cause is usually a failed radiator pressure cap (allowing system pressure to spike) or a minor head gasket issue. We diagnose the root cause accurately — not just address the visible symptom.
The joints where individual copper tubes meet the header plate inside the radiator can fail internally — coolant leaks into the air-side of the radiator without any visible external drip. Symptoms include unexplained coolant loss and white steam from the radiator. Diagnosed by pressure testing and repaired by re-rolling or re-soldering the tube joints.
✓ Most DG set radiator leaks are copper-brass — repaired in 1–2 days
✓ For 24×7 CAT/Cummins sets — consider copper-brass upgrade to avoid repeat leaks
Alt text: "DG set radiator copper-brass soldering repair in progress — Ajanta Radiators Worli Mumbai workshop"
Send photos of the leak area and your DG set brand and KVA. We give an initial assessment and arrange pickup.
We pick up from your Mumbai location or you bring it to our Worli workshop. Same-day collection available for urgent jobs.
Radiator pressurised to operating pressure in a water tank. All leak points — visible and hidden — identified before any repair starts.
We advise: repair only, repair + partial recore, or full recore. We never recommend more work than is actually needed.
Soldering for copper-brass, TIG welding or epoxy for aluminium. All identified leak points fixed — not just the obvious one.
Repaired radiator pressure tested again to confirm zero leaks across the full radiator before it leaves our workshop.
Returned to your Mumbai location. 6-month warranty — if it leaks at the repaired area within 6 months, we fix it free.
We repair leaks in DG set radiators for all major brands used in India. Select your brand for brand-specific leak causes and repair details:
Established 1970, Worli Mumbai. We have diagnosed and repaired thousands of DG set radiator leaks across all brands and KVA ratings. Experience matters when diagnosing hidden leaks correctly.
Copper-brass soldering and aluminium TIG welding both done in-house at our Worli workshop. Not outsourced — we handle any DG set radiator leak regardless of material type.
We pressure test the full radiator before and after repair — not just the obvious leak point. Every leak identified and fixed in one visit. No repeat trips for secondary leaks we missed.
We tell you honestly whether repair is sufficient or whether recoring makes more economic sense. We never recommend a recore if repair is the right answer — and never repair when recoring would save you more money long-term.
6-month warranty on every leak repair. Leak returns at the repaired area within 6 months — we fix it at no charge. Every repair pressure tested before delivery.
We collect leaking DG set radiators from anywhere in Mumbai. Urgent collection possible for critical DG sets. Repaired radiator returned to your site with warranty.
We strongly advise against using radiator stop-leak sealant on DG set radiators. Stop-leak products can temporarily mask a leak but they also clog the fine passages inside the radiator core, reducing cooling efficiency significantly. In many cases, stop-leak sealant causes more damage than the original leak. The correct approach is to repair the leak properly by soldering or welding at our workshop — which costs less in the long run and does not compromise cooling performance.
Invisible coolant loss is usually caused by one of three things: an internal tube-to-header joint failure (coolant leaks into the air side of the radiator and evaporates as steam), a failed pressure cap (coolant pushed out through the overflow pipe under excess pressure), or a minor head gasket leak (coolant enters the combustion chamber and burns off as white smoke). We pressure test the full radiator to identify internal leaks. If the radiator checks out clean, the issue lies elsewhere in the cooling circuit.
Most single-point leak repairs — a cracked tank joint, hose nipple leak, or one or two tube failures — are completed in 1–2 working days at our Worli workshop. Multiple leak points or leaks requiring tank fabrication may take 2–3 working days. We give you a confirmed timeline after we receive the radiator and complete the initial pressure test and assessment.
For an isolated leak — one or two specific failure points — repair is almost always the right answer. It costs a fraction of replacement and restores full function. Replacement (or recoring) makes more sense when the core has multiple widespread failures, is heavily corroded, or has been repaired several times in the same area. We give you an honest assessment after pressure testing the radiator — we will recommend the most cost-effective solution, not the most expensive one.
Yes — we repair aluminium pinhole leaks by TIG welding. For 1–3 isolated pinholes on a relatively new core, TIG welding is a practical and cost-effective solution. However, if your CAT radiator has multiple pinholes appearing repeatedly or the core is 5+ years old on a 24×7 running DG set, we recommend a copper-brass core upgrade instead of repeated pinhole repairs. The upgrade eliminates the recurring electrolytic corrosion problem permanently.
Yes. We arrange pickup from anywhere in Mumbai — including Andheri, Thane, Navi Mumbai, BKC, Worli, Dharavi, Dombivli, Bhiwandi, Vasai, Borivali, Chembur and surrounding areas. For critical DG sets (hospitals, data centres, factories), we prioritise urgent collection. Once repaired and pressure tested, we deliver the radiator back to your location with a 6-month warranty on the work done.
Switch off your DG set, let it cool, then send us photos of the leak and your DG set brand and KVA on WhatsApp. We respond within the hour with a pickup arrangement and repair estimate.